Add named locomotive availability runtime surface

README.md

@@ -51,11 +51,15 @@ recovered locomotives-page `real_packed_v1` record that lands in the explicit
 `blocked_unmapped_world_descriptor` bucket. The next recovered descriptor band is now partially
 executable too: descriptors `454..456` (`All Steam/Diesel/Electric Locos Avail.`) now lower
 through checked-in metadata into keyed `world_flags`, while the wider locomotive availability/cost
-scalar bands remain recovered-but-parity-only until per-locomotive identity is grounded. Explicit
+scalar bands remain recovered-but-parity-only until per-locomotive identity is grounded. The
-unmapped world-condition and world-descriptor frontier buckets still remain where current
+runtime now carries the save-owned named locomotive availability table directly too: checked-in
-checked-in metadata stops. Shell purchase-flow and selected-profile parity remain out of scope.
+save-slice documents can populate `RuntimeState.named_locomotive_availability`, and imported
-Mixed supported/unsupported real rows still stay parity-only. The PE32 hook remains useful as
+runtime effects can mutate that map through the ordinary event-service path without needing full
-capture and integration tooling, but it is no longer the main execution milestone.
+Trainbuy or live-locomotive parity. Explicit unmapped world-condition and world-descriptor
+frontier buckets still remain where current checked-in metadata stops. Shell purchase-flow and
+selected-profile parity remain out of scope. Mixed supported/unsupported real rows still stay
+parity-only. The PE32 hook remains useful as capture and integration tooling, but it is no longer
+the main execution milestone.
 
 ## Project Docs
 

crates/rrt-cli/src/main.rs

@@ -4454,6 +4454,9 @@ mod tests {
         let mixed_overlay_fixture = PathBuf::from(env!("CARGO_MANIFEST_DIR")).join(
             "../../fixtures/runtime/packed-event-mixed-company-descriptor-overlay-fixture.json",
         );
+        let named_locomotive_fixture = PathBuf::from(env!("CARGO_MANIFEST_DIR")).join(
+            "../../fixtures/runtime/packed-event-named-locomotive-availability-save-slice-fixture.json",
+        );
 
         run_runtime_summarize_fixture(&parity_fixture)
             .expect("save-slice-backed parity fixture should summarize");
@@ -4471,6 +4474,8 @@ mod tests {
             .expect("overlay-backed track-capacity fixture should summarize");
         run_runtime_summarize_fixture(&mixed_overlay_fixture)
             .expect("overlay-backed mixed real-row fixture should summarize");
+        run_runtime_summarize_fixture(&named_locomotive_fixture)
+            .expect("save-slice-backed named locomotive availability fixture should summarize");
     }
 
     #[test]
@@ -4495,6 +4500,7 @@ mod tests {
                 bridge_family: None,
                 profile: None,
                 candidate_availability_table: None,
+                named_locomotive_availability_table: None,
                 special_conditions_table: None,
                 event_runtime_collection: None,
                 notes: vec!["exported for test".to_string()],

crates/rrt-fixtures/src/load.rs

@@ -183,6 +183,7 @@ mod tests {
                 packed_event_collection: None,
                 event_runtime_records: Vec::new(),
                 candidate_availability: BTreeMap::new(),
+                named_locomotive_availability: BTreeMap::new(),
                 special_conditions: BTreeMap::new(),
                 service_state: RuntimeServiceState::default(),
             },
@@ -259,6 +260,7 @@ mod tests {
                 bridge_family: None,
                 profile: None,
                 candidate_availability_table: None,
+                named_locomotive_availability_table: None,
                 special_conditions_table: None,
                 event_runtime_collection: None,
                 notes: vec![],
@@ -352,6 +354,7 @@ mod tests {
                 packed_event_collection: None,
                 event_runtime_records: Vec::new(),
                 candidate_availability: BTreeMap::new(),
+                named_locomotive_availability: BTreeMap::new(),
                 special_conditions: BTreeMap::new(),
                 service_state: RuntimeServiceState::default(),
             },
@@ -371,6 +374,7 @@ mod tests {
                 bridge_family: None,
                 profile: None,
                 candidate_availability_table: None,
+                named_locomotive_availability_table: None,
                 special_conditions_table: None,
                 event_runtime_collection: Some(
                     rrt_runtime::SmpLoadedEventRuntimeCollectionSummary {

crates/rrt-fixtures/src/schema.rs

@@ -150,6 +150,10 @@ pub struct ExpectedRuntimeSummary {
     #[serde(default)]
     pub zero_candidate_availability_count: Option<usize>,
     #[serde(default)]
+    pub named_locomotive_availability_count: Option<usize>,
+    #[serde(default)]
+    pub zero_named_locomotive_availability_count: Option<usize>,
+    #[serde(default)]
     pub special_condition_count: Option<usize>,
     #[serde(default)]
     pub enabled_special_condition_count: Option<usize>,
@@ -735,6 +739,22 @@ impl ExpectedRuntimeSummary {
                 ));
             }
         }
+        if let Some(count) = self.named_locomotive_availability_count {
+            if actual.named_locomotive_availability_count != count {
+                mismatches.push(format!(
+                    "named_locomotive_availability_count mismatch: expected {count}, got {}",
+                    actual.named_locomotive_availability_count
+                ));
+            }
+        }
+        if let Some(count) = self.zero_named_locomotive_availability_count {
+            if actual.zero_named_locomotive_availability_count != count {
+                mismatches.push(format!(
+                    "zero_named_locomotive_availability_count mismatch: expected {count}, got {}",
+                    actual.zero_named_locomotive_availability_count
+                ));
+            }
+        }
         if let Some(count) = self.special_condition_count {
             if actual.special_condition_count != count {
                 mismatches.push(format!(

crates/rrt-runtime/src/import.rs

@@ -94,6 +94,7 @@ struct SaveSliceProjection {
     packed_event_collection: Option<RuntimePackedEventCollectionSummary>,
     event_runtime_records: Vec<RuntimeEventRecord>,
     candidate_availability: BTreeMap<String, u32>,
+    named_locomotive_availability: BTreeMap<String, u32>,
     special_conditions: BTreeMap<String, u32>,
 }
 
@@ -238,6 +239,7 @@ pub fn project_save_slice_to_runtime_state_import(
         packed_event_collection: projection.packed_event_collection,
         event_runtime_records: projection.event_runtime_records,
         candidate_availability: projection.candidate_availability,
+        named_locomotive_availability: projection.named_locomotive_availability,
         special_conditions: projection.special_conditions,
         service_state: RuntimeServiceState::default(),
     };
@@ -295,6 +297,7 @@ pub fn project_save_slice_overlay_to_runtime_state_import(
         packed_event_collection: projection.packed_event_collection,
         event_runtime_records: projection.event_runtime_records,
         candidate_availability: projection.candidate_availability,
+        named_locomotive_availability: projection.named_locomotive_availability,
         special_conditions: projection.special_conditions,
         service_state: base_state.service_state.clone(),
     };
@@ -325,6 +328,10 @@ fn project_save_slice_components(
         "save_slice.special_conditions_present".to_string(),
         save_slice.special_conditions_table.is_some(),
     );
+    world_flags.insert(
+        "save_slice.named_locomotive_availability_present".to_string(),
+        save_slice.named_locomotive_availability_table.is_some(),
+    );
     world_flags.insert(
         "save_slice.event_runtime_collection_present".to_string(),
         save_slice.event_runtime_collection.is_some(),
@@ -590,6 +597,35 @@ fn project_save_slice_components(
         }
     }
 
+    let mut named_locomotive_availability = BTreeMap::new();
+    if let Some(table) = &save_slice.named_locomotive_availability_table {
+        metadata.insert(
+            "save_slice.named_locomotive_availability_source_kind".to_string(),
+            table.source_kind.clone(),
+        );
+        metadata.insert(
+            "save_slice.named_locomotive_availability_semantic_family".to_string(),
+            table.semantic_family.clone(),
+        );
+        metadata.insert(
+            "save_slice.named_locomotive_availability_entry_count".to_string(),
+            table.observed_entry_count.to_string(),
+        );
+        metadata.insert(
+            "save_slice.named_locomotive_availability_zero_count".to_string(),
+            table.zero_availability_count.to_string(),
+        );
+        if let Some(header_offset) = table.header_offset {
+            metadata.insert(
+                "save_slice.named_locomotive_availability_header_offset".to_string(),
+                header_offset.to_string(),
+            );
+        }
+        for entry in &table.entries {
+            named_locomotive_availability.insert(entry.text.clone(), entry.availability_dword);
+        }
+    }
+
     for (index, note) in save_slice.notes.iter().enumerate() {
         metadata.insert(format!("save_slice.note.{index}"), note.clone());
     }
@@ -602,6 +638,7 @@ fn project_save_slice_components(
         packed_event_collection,
         event_runtime_records,
         candidate_availability,
+        named_locomotive_availability,
         special_conditions,
     })
 }
@@ -1133,6 +1170,12 @@ fn lower_condition_targets_in_effect(
                 value: *value,
             }
         }
+        RuntimeEffect::SetNamedLocomotiveAvailability { name, value } => {
+            RuntimeEffect::SetNamedLocomotiveAvailability {
+                name: name.clone(),
+                value: *value,
+            }
+        }
         RuntimeEffect::SetSpecialCondition { label, value } => RuntimeEffect::SetSpecialCondition {
             label: label.clone(),
             value: *value,
@@ -1562,6 +1605,12 @@ fn smp_runtime_effect_to_runtime_effect(
                 value: *value,
             })
         }
+        RuntimeEffect::SetNamedLocomotiveAvailability { name, value } => {
+            Ok(RuntimeEffect::SetNamedLocomotiveAvailability {
+                name: name.clone(),
+                value: *value,
+            })
+        }
         RuntimeEffect::SetSpecialCondition { label, value } => {
             Ok(RuntimeEffect::SetSpecialCondition {
                 label: label.clone(),
@@ -2111,6 +2160,7 @@ fn runtime_effect_uses_condition_true_company(effect: &RuntimeEffect) -> bool {
         | RuntimeEffect::SetPlayerCash { .. }
         | RuntimeEffect::DeactivatePlayer { .. }
         | RuntimeEffect::SetCandidateAvailability { .. }
+        | RuntimeEffect::SetNamedLocomotiveAvailability { .. }
         | RuntimeEffect::SetSpecialCondition { .. }
         | RuntimeEffect::ActivateEventRecord { .. }
         | RuntimeEffect::DeactivateEventRecord { .. }
@@ -2188,6 +2238,7 @@ fn runtime_effect_company_target_import_blocker(
         | RuntimeEffect::SetLimitedTrackBuildingAmount { .. }
         | RuntimeEffect::SetEconomicStatusCode { .. }
         | RuntimeEffect::SetCandidateAvailability { .. }
+        | RuntimeEffect::SetNamedLocomotiveAvailability { .. }
         | RuntimeEffect::SetSpecialCondition { .. }
         | RuntimeEffect::ActivateEventRecord { .. }
         | RuntimeEffect::DeactivateEventRecord { .. }
@@ -2526,6 +2577,7 @@ mod tests {
             packed_event_collection: None,
             event_runtime_records: Vec::new(),
             candidate_availability: BTreeMap::new(),
+            named_locomotive_availability: BTreeMap::new(),
             special_conditions: BTreeMap::new(),
             service_state: RuntimeServiceState::default(),
         }
@@ -3080,6 +3132,7 @@ mod tests {
                 bridge_family: None,
                 profile: None,
                 candidate_availability_table: None,
+                named_locomotive_availability_table: None,
                 special_conditions_table: None,
                 event_runtime_collection: None,
                 notes: vec![],
@@ -3118,6 +3171,7 @@ mod tests {
                 bridge_family: None,
                 profile: None,
                 candidate_availability_table: None,
+                named_locomotive_availability_table: None,
                 special_conditions_table: None,
                 event_runtime_collection: None,
                 notes: vec![],
@@ -3199,6 +3253,38 @@ mod tests {
                     },
                 ],
             }),
+            named_locomotive_availability_table: Some(
+                crate::SmpLoadedNamedLocomotiveAvailabilityTable {
+                    source_kind: "runtime-save-direct-serializer".to_string(),
+                    semantic_family: "scenario-named-locomotive-availability-table".to_string(),
+                    header_offset: None,
+                    entries_offset: None,
+                    entries_end_offset: None,
+                    observed_entry_count: 2,
+                    zero_availability_count: 1,
+                    zero_availability_names: vec!["Big Boy".to_string()],
+                    entries: vec![
+                        crate::SmpRt3105SaveNameTableEntry {
+                            index: 0,
+                            offset: 0,
+                            text: "Big Boy".to_string(),
+                            availability_dword: 0,
+                            availability_dword_hex: "0x00000000".to_string(),
+                            trailer_word: 0,
+                            trailer_word_hex: "0x00000000".to_string(),
+                        },
+                        crate::SmpRt3105SaveNameTableEntry {
+                            index: 1,
+                            offset: 0x41,
+                            text: "GP7".to_string(),
+                            availability_dword: 1,
+                            availability_dword_hex: "0x00000001".to_string(),
+                            trailer_word: 1,
+                            trailer_word_hex: "0x00000001".to_string(),
+                        },
+                    ],
+                },
+            ),
             special_conditions_table: Some(crate::SmpLoadedSpecialConditionsTable {
                 source_kind: "save-fixed-special-conditions-range".to_string(),
                 table_offset: 0x0d64,
@@ -3444,10 +3530,34 @@ mod tests {
             import.state.candidate_availability.get("Uranium Mine"),
             Some(&0)
         );
+        assert_eq!(
+            import.state.named_locomotive_availability.get("Big Boy"),
+            Some(&0)
+        );
+        assert_eq!(
+            import.state.named_locomotive_availability.get("GP7"),
+            Some(&1)
+        );
         assert_eq!(
             import.state.special_conditions.get("Disable Cargo Economy"),
             Some(&0)
         );
+        assert_eq!(
+            import
+                .state
+                .metadata
+                .get("save_slice.named_locomotive_availability_source_kind")
+                .map(String::as_str),
+            Some("runtime-save-direct-serializer")
+        );
+        assert_eq!(
+            import
+                .state
+                .metadata
+                .get("save_slice.named_locomotive_availability_entry_count")
+                .map(String::as_str),
+            Some("2")
+        );
         assert_eq!(
             import
                 .state
@@ -3485,6 +3595,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -3598,6 +3709,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -3689,6 +3801,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -3798,6 +3911,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -3880,6 +3994,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -4012,6 +4127,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -4252,6 +4368,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -4327,6 +4444,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -4424,6 +4542,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -4496,6 +4615,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -4615,6 +4735,7 @@ mod tests {
             packed_event_collection: None,
             event_runtime_records: Vec::new(),
             candidate_availability: BTreeMap::new(),
+            named_locomotive_availability: BTreeMap::new(),
             special_conditions: BTreeMap::new(),
             service_state: RuntimeServiceState::default(),
         };
@@ -4627,6 +4748,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -4769,6 +4891,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -4871,6 +4994,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -4954,6 +5078,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -5058,6 +5183,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -5162,6 +5288,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -5256,6 +5383,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -5346,6 +5474,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -5444,6 +5573,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -5533,6 +5663,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -5604,6 +5735,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -5680,6 +5812,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -5761,6 +5894,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -5842,6 +5976,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -5939,6 +6074,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -6027,6 +6163,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -6141,6 +6278,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -6264,6 +6402,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -6372,6 +6511,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -6543,6 +6683,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -6634,6 +6775,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -6721,6 +6863,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -6873,6 +7016,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -7014,6 +7158,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -7102,6 +7247,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -7217,6 +7363,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -7320,6 +7467,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -7443,6 +7591,7 @@ mod tests {
                 effects: vec![],
             }],
             candidate_availability: BTreeMap::new(),
+            named_locomotive_availability: BTreeMap::new(),
             special_conditions: BTreeMap::new(),
             service_state: RuntimeServiceState {
                 periodic_boundary_calls: 9,
@@ -7460,6 +7609,7 @@ mod tests {
             bridge_family: None,
             profile: None,
             candidate_availability_table: None,
+            named_locomotive_availability_table: None,
             special_conditions_table: None,
             event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                 source_kind: "packed-event-runtime-collection".to_string(),
@@ -7609,6 +7759,7 @@ mod tests {
                 packed_event_collection: None,
                 event_runtime_records: Vec::new(),
                 candidate_availability: BTreeMap::new(),
+                named_locomotive_availability: BTreeMap::new(),
                 special_conditions: BTreeMap::new(),
                 service_state: RuntimeServiceState::default(),
             },
@@ -7629,6 +7780,7 @@ mod tests {
                 bridge_family: None,
                 profile: None,
                 candidate_availability_table: None,
+                named_locomotive_availability_table: None,
                 special_conditions_table: None,
                 event_runtime_collection: Some(crate::SmpLoadedEventRuntimeCollectionSummary {
                     source_kind: "packed-event-runtime-collection".to_string(),

crates/rrt-runtime/src/lib.rs

@@ -53,10 +53,11 @@ pub use smp::{
     SmpClassicRehydrateProfileProbe, SmpContainerProfile, SmpEarlyContentProbe,
     SmpHeaderVariantProbe, SmpInspectionReport, SmpKnownTagHit,
     SmpLoadedCandidateAvailabilityTable, SmpLoadedEventRuntimeCollectionSummary,
-    SmpLoadedPackedEventCompactControlSummary, SmpLoadedPackedEventConditionRowSummary,
+    SmpLoadedNamedLocomotiveAvailabilityTable, SmpLoadedPackedEventCompactControlSummary,
-    SmpLoadedPackedEventGroupedEffectRowSummary, SmpLoadedPackedEventNegativeSentinelScopeSummary,
+    SmpLoadedPackedEventConditionRowSummary, SmpLoadedPackedEventGroupedEffectRowSummary,
-    SmpLoadedPackedEventRecordSummary, SmpLoadedPackedEventTextBandSummary, SmpLoadedProfile,
+    SmpLoadedPackedEventNegativeSentinelScopeSummary, SmpLoadedPackedEventRecordSummary,
-    SmpLoadedSaveSlice, SmpLoadedSpecialConditionsTable, SmpLocomotivePolicyFieldObservation,
+    SmpLoadedPackedEventTextBandSummary, SmpLoadedProfile, SmpLoadedSaveSlice,
+    SmpLoadedSpecialConditionsTable, SmpLocomotivePolicyFieldObservation,
     SmpLocomotivePolicyFloatAlignmentCandidate, SmpLocomotivePolicyNeighborhoodProbe,
     SmpPackedProfileWordLane, SmpPostSpecialConditionsScalarLane,
     SmpPostSpecialConditionsScalarProbe, SmpPostTextFieldNeighborhoodProbe,

crates/rrt-runtime/src/persistence.rs

@@ -103,6 +103,7 @@ mod tests {
                 packed_event_collection: None,
                 event_runtime_records: Vec::new(),
                 candidate_availability: BTreeMap::new(),
+                named_locomotive_availability: BTreeMap::new(),
                 special_conditions: BTreeMap::new(),
                 service_state: RuntimeServiceState::default(),
             },

crates/rrt-runtime/src/runtime.rs

@@ -307,6 +307,10 @@ pub enum RuntimeEffect {
         name: String,
         value: u32,
     },
+    SetNamedLocomotiveAvailability {
+        name: String,
+        value: bool,
+    },
     SetSpecialCondition {
         label: String,
         value: u32,
@@ -637,6 +641,8 @@ pub struct RuntimeState {
     #[serde(default)]
     pub candidate_availability: BTreeMap<String, u32>,
     #[serde(default)]
+    pub named_locomotive_availability: BTreeMap<String, u32>,
+    #[serde(default)]
     pub special_conditions: BTreeMap<String, u32>,
     #[serde(default)]
     pub service_state: RuntimeServiceState,
@@ -1119,6 +1125,11 @@ impl RuntimeState {
                 return Err("candidate_availability contains an empty key".to_string());
             }
         }
+        for key in self.named_locomotive_availability.keys() {
+            if key.trim().is_empty() {
+                return Err("named_locomotive_availability contains an empty key".to_string());
+            }
+        }
         for key in self.special_conditions.keys() {
             if key.trim().is_empty() {
                 return Err("special_conditions contains an empty key".to_string());
@@ -1190,6 +1201,11 @@ fn validate_runtime_effect(
                 return Err("name must not be empty".to_string());
             }
         }
+        RuntimeEffect::SetNamedLocomotiveAvailability { name, .. } => {
+            if name.trim().is_empty() {
+                return Err("name must not be empty".to_string());
+            }
+        }
         RuntimeEffect::SetSpecialCondition { label, .. } => {
             if label.trim().is_empty() {
                 return Err("label must not be empty".to_string());
@@ -1409,6 +1425,7 @@ mod tests {
             packed_event_collection: None,
             event_runtime_records: Vec::new(),
             candidate_availability: BTreeMap::new(),
+            named_locomotive_availability: BTreeMap::new(),
             special_conditions: BTreeMap::new(),
             service_state: RuntimeServiceState::default(),
         };
@@ -1464,6 +1481,7 @@ mod tests {
             packed_event_collection: None,
             event_runtime_records: Vec::new(),
             candidate_availability: BTreeMap::new(),
+            named_locomotive_availability: BTreeMap::new(),
             special_conditions: BTreeMap::new(),
             service_state: RuntimeServiceState::default(),
         };
@@ -1518,6 +1536,7 @@ mod tests {
                 }],
             }],
             candidate_availability: BTreeMap::new(),
+            named_locomotive_availability: BTreeMap::new(),
             special_conditions: BTreeMap::new(),
             service_state: RuntimeServiceState::default(),
         };
@@ -1582,6 +1601,7 @@ mod tests {
                 }],
             }],
             candidate_availability: BTreeMap::new(),
+            named_locomotive_availability: BTreeMap::new(),
             special_conditions: BTreeMap::new(),
             service_state: RuntimeServiceState::default(),
         };
@@ -1677,6 +1697,7 @@ mod tests {
             }),
             event_runtime_records: Vec::new(),
             candidate_availability: BTreeMap::new(),
+            named_locomotive_availability: BTreeMap::new(),
             special_conditions: BTreeMap::new(),
             service_state: RuntimeServiceState::default(),
         };
@@ -1718,6 +1739,7 @@ mod tests {
             packed_event_collection: None,
             event_runtime_records: Vec::new(),
             candidate_availability: BTreeMap::new(),
+            named_locomotive_availability: BTreeMap::new(),
             special_conditions: BTreeMap::new(),
             service_state: RuntimeServiceState::default(),
         };
@@ -1759,6 +1781,7 @@ mod tests {
             packed_event_collection: None,
             event_runtime_records: Vec::new(),
             candidate_availability: BTreeMap::new(),
+            named_locomotive_availability: BTreeMap::new(),
             special_conditions: BTreeMap::new(),
             service_state: RuntimeServiceState::default(),
         };
@@ -1817,6 +1840,7 @@ mod tests {
             packed_event_collection: None,
             event_runtime_records: Vec::new(),
             candidate_availability: BTreeMap::new(),
+            named_locomotive_availability: BTreeMap::new(),
             special_conditions: BTreeMap::new(),
             service_state: RuntimeServiceState::default(),
         };
@@ -1865,6 +1889,7 @@ mod tests {
             packed_event_collection: None,
             event_runtime_records: Vec::new(),
             candidate_availability: BTreeMap::new(),
+            named_locomotive_availability: BTreeMap::new(),
             special_conditions: BTreeMap::new(),
             service_state: RuntimeServiceState::default(),
         };
@@ -1917,6 +1942,7 @@ mod tests {
             packed_event_collection: None,
             event_runtime_records: Vec::new(),
             candidate_availability: BTreeMap::new(),
+            named_locomotive_availability: BTreeMap::new(),
             special_conditions: BTreeMap::new(),
             service_state: RuntimeServiceState::default(),
         };
@@ -1965,6 +1991,7 @@ mod tests {
             packed_event_collection: None,
             event_runtime_records: Vec::new(),
             candidate_availability: BTreeMap::new(),
+            named_locomotive_availability: BTreeMap::new(),
             special_conditions: BTreeMap::new(),
             service_state: RuntimeServiceState::default(),
         };
@@ -2019,6 +2046,7 @@ mod tests {
             packed_event_collection: None,
             event_runtime_records: Vec::new(),
             candidate_availability: BTreeMap::new(),
+            named_locomotive_availability: BTreeMap::new(),
             special_conditions: BTreeMap::new(),
             service_state: RuntimeServiceState::default(),
         };
@@ -2067,6 +2095,7 @@ mod tests {
             packed_event_collection: None,
             event_runtime_records: Vec::new(),
             candidate_availability: BTreeMap::new(),
+            named_locomotive_availability: BTreeMap::new(),
             special_conditions: BTreeMap::new(),
             service_state: RuntimeServiceState::default(),
         };
@@ -2115,6 +2144,7 @@ mod tests {
             packed_event_collection: None,
             event_runtime_records: Vec::new(),
             candidate_availability: BTreeMap::new(),
+            named_locomotive_availability: BTreeMap::new(),
             special_conditions: BTreeMap::new(),
             service_state: RuntimeServiceState::default(),
         };

crates/rrt-runtime/src/smp.rs

@@ -1503,6 +1503,22 @@ pub struct SmpLoadedCandidateAvailabilityTable {
     pub entries: Vec<SmpRt3105SaveNameTableEntry>,
 }
 
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+pub struct SmpLoadedNamedLocomotiveAvailabilityTable {
+    pub source_kind: String,
+    pub semantic_family: String,
+    #[serde(default)]
+    pub header_offset: Option<usize>,
+    #[serde(default)]
+    pub entries_offset: Option<usize>,
+    #[serde(default)]
+    pub entries_end_offset: Option<usize>,
+    pub observed_entry_count: usize,
+    pub zero_availability_count: usize,
+    pub zero_availability_names: Vec<String>,
+    pub entries: Vec<SmpRt3105SaveNameTableEntry>,
+}
+
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub struct SmpLoadedSpecialConditionsTable {
     pub source_kind: String,
@@ -1673,6 +1689,7 @@ pub struct SmpLoadedSaveSlice {
     pub bridge_family: Option<String>,
     pub profile: Option<SmpLoadedProfile>,
     pub candidate_availability_table: Option<SmpLoadedCandidateAvailabilityTable>,
+    pub named_locomotive_availability_table: Option<SmpLoadedNamedLocomotiveAvailabilityTable>,
     pub special_conditions_table: Option<SmpLoadedSpecialConditionsTable>,
     pub event_runtime_collection: Option<SmpLoadedEventRuntimeCollectionSummary>,
     pub notes: Vec<String>,
@@ -1840,6 +1857,7 @@ pub fn load_save_slice_from_report(
         bridge_family: summary.bridge_family.clone(),
         profile,
         candidate_availability_table,
+        named_locomotive_availability_table: None,
         special_conditions_table,
         event_runtime_collection: report.event_runtime_collection_summary.clone(),
         notes: summary.notes.clone(),
@@ -2659,6 +2677,11 @@ fn parse_real_grouped_effect_row_summary(
     if descriptor_metadata.is_none() {
         notes.push("descriptor id not yet recovered in the checked-in effect table".to_string());
     }
+    if let Some(loco_id) = recovered_locomotive_availability_loco_id(descriptor_id) {
+        notes.push(format!(
+            "locomotive availability descriptor maps to live locomotive id {loco_id}"
+        ));
+    }
 
     Some(SmpLoadedPackedEventGroupedEffectRowSummary {
         group_index,
@@ -2836,6 +2859,16 @@ fn recovered_locomotive_availability_descriptor_metadata(
         })
 }
 
+fn recovered_locomotive_availability_loco_id(descriptor_id: u32) -> Option<u32> {
+    if (241..=351).contains(&descriptor_id) {
+        return Some(descriptor_id - 240);
+    }
+    if (457..=474).contains(&descriptor_id) {
+        return Some(descriptor_id - 345);
+    }
+    None
+}
+
 fn recovered_locomotive_cost_descriptor_metadata(
     descriptor_id: u32,
 ) -> Option<RealGroupedEffectDescriptorMetadata> {
@@ -3409,6 +3442,7 @@ fn runtime_effect_supported_for_save_import(effect: &RuntimeEffect) -> bool {
         | RuntimeEffect::SetLimitedTrackBuildingAmount { .. }
         | RuntimeEffect::SetEconomicStatusCode { .. }
         | RuntimeEffect::SetCandidateAvailability { .. }
+        | RuntimeEffect::SetNamedLocomotiveAvailability { .. }
         | RuntimeEffect::SetSpecialCondition { .. }
         | RuntimeEffect::ConfiscateCompanyAssets { .. }
         | RuntimeEffect::DeactivateCompany { .. }

crates/rrt-runtime/src/step.rs

@@ -490,6 +490,11 @@ fn apply_runtime_effects(
             RuntimeEffect::SetCandidateAvailability { name, value } => {
                 state.candidate_availability.insert(name.clone(), *value);
             }
+            RuntimeEffect::SetNamedLocomotiveAvailability { name, value } => {
+                state
+                    .named_locomotive_availability
+                    .insert(name.clone(), u32::from(*value));
+            }
             RuntimeEffect::SetSpecialCondition { label, value } => {
                 state.special_conditions.insert(label.clone(), *value);
             }
@@ -1158,6 +1163,7 @@ mod tests {
             packed_event_collection: None,
             event_runtime_records: Vec::new(),
             candidate_availability: BTreeMap::new(),
+            named_locomotive_availability: BTreeMap::new(),
             special_conditions: BTreeMap::new(),
             service_state: RuntimeServiceState::default(),
         }
@@ -1372,6 +1378,43 @@ mod tests {
         assert_eq!(result.service_events[0].mutated_company_ids, vec![2]);
     }
 
+    #[test]
+    fn applies_named_locomotive_availability_effects() {
+        let mut state = RuntimeState {
+            event_runtime_records: vec![RuntimeEventRecord {
+                record_id: 10,
+                trigger_kind: 7,
+                active: true,
+                service_count: 0,
+                marks_collection_dirty: false,
+                one_shot: false,
+                has_fired: false,
+                conditions: Vec::new(),
+                effects: vec![
+                    RuntimeEffect::SetNamedLocomotiveAvailability {
+                        name: "Big Boy".to_string(),
+                        value: false,
+                    },
+                    RuntimeEffect::SetNamedLocomotiveAvailability {
+                        name: "GP7".to_string(),
+                        value: true,
+                    },
+                ],
+            }],
+            ..state()
+        };
+
+        let result = execute_step_command(
+            &mut state,
+            &StepCommand::ServiceTriggerKind { trigger_kind: 7 },
+        )
+        .expect("named locomotive availability effects should succeed");
+
+        assert_eq!(state.named_locomotive_availability.get("Big Boy"), Some(&0));
+        assert_eq!(state.named_locomotive_availability.get("GP7"), Some(&1));
+        assert_eq!(result.service_events[0].applied_effect_count, 2);
+    }
+
     #[test]
     fn resolves_symbolic_company_targets() {
         let mut state = RuntimeState {

crates/rrt-runtime/src/summary.rs

@@ -72,6 +72,8 @@ pub struct RuntimeSummary {
     pub event_runtime_record_count: usize,
     pub candidate_availability_count: usize,
     pub zero_candidate_availability_count: usize,
+    pub named_locomotive_availability_count: usize,
+    pub zero_named_locomotive_availability_count: usize,
     pub special_condition_count: usize,
     pub enabled_special_condition_count: usize,
     pub save_profile_kind: Option<String>,
@@ -570,6 +572,12 @@ impl RuntimeSummary {
                 .values()
                 .filter(|value| **value == 0)
                 .count(),
+            named_locomotive_availability_count: state.named_locomotive_availability.len(),
+            zero_named_locomotive_availability_count: state
+                .named_locomotive_availability
+                .values()
+                .filter(|value| **value == 0)
+                .count(),
             special_condition_count: state.special_conditions.len(),
             enabled_special_condition_count: state
                 .special_conditions
@@ -781,6 +789,7 @@ mod tests {
             }),
             event_runtime_records: Vec::new(),
             candidate_availability: BTreeMap::new(),
+            named_locomotive_availability: BTreeMap::new(),
             special_conditions: BTreeMap::new(),
             service_state: RuntimeServiceState::default(),
         };
@@ -869,6 +878,7 @@ mod tests {
             packed_event_collection: None,
             event_runtime_records: Vec::new(),
             candidate_availability: BTreeMap::new(),
+            named_locomotive_availability: BTreeMap::new(),
             special_conditions: BTreeMap::new(),
             service_state: RuntimeServiceState::default(),
         };
@@ -878,6 +888,44 @@ mod tests {
         assert_eq!(summary.active_company_count, 1);
     }
 
+    #[test]
+    fn counts_named_locomotive_availability_entries_and_zero_values() {
+        let state = RuntimeState {
+            calendar: CalendarPoint {
+                year: 1830,
+                month_slot: 0,
+                phase_slot: 0,
+                tick_slot: 0,
+            },
+            world_flags: BTreeMap::new(),
+            save_profile: RuntimeSaveProfileState::default(),
+            world_restore: RuntimeWorldRestoreState::default(),
+            metadata: BTreeMap::new(),
+            companies: Vec::new(),
+            selected_company_id: None,
+            players: Vec::new(),
+            selected_player_id: None,
+            trains: Vec::new(),
+            territories: Vec::new(),
+            company_territory_track_piece_counts: Vec::new(),
+            company_territory_access: Vec::new(),
+            packed_event_collection: None,
+            event_runtime_records: Vec::new(),
+            candidate_availability: BTreeMap::new(),
+            named_locomotive_availability: BTreeMap::from([
+                ("Big Boy".to_string(), 0),
+                ("GP7".to_string(), 1),
+                ("Mikado".to_string(), 0),
+            ]),
+            special_conditions: BTreeMap::new(),
+            service_state: RuntimeServiceState::default(),
+        };
+
+        let summary = RuntimeSummary::from_state(&state);
+        assert_eq!(summary.named_locomotive_availability_count, 3);
+        assert_eq!(summary.zero_named_locomotive_availability_count, 2);
+    }
+
     #[test]
     fn counts_world_frontier_buckets_separately() {
         let state = RuntimeState {
@@ -966,6 +1014,7 @@ mod tests {
             }),
             event_runtime_records: Vec::new(),
             candidate_availability: BTreeMap::new(),
+            named_locomotive_availability: BTreeMap::new(),
             special_conditions: BTreeMap::new(),
             service_state: RuntimeServiceState::default(),
         };

docs/README.md

@@ -127,6 +127,10 @@ The highest-value next passes are now:
   descriptors `454..456` (`All Steam/Diesel/Electric Locos Avail.`) now lower through checked-in
   metadata into keyed `world_flags`, while the wider locomotive availability/cost scalar bands
   remain recovered-but-parity-only until per-locomotive identity is grounded
+- the runtime now also carries the save-owned named locomotive availability table directly:
+  checked-in save-slice documents can populate `RuntimeState.named_locomotive_availability`, and
+  imported runtime effects can mutate that map through the ordinary event-service path without
+  needing full live locomotive-pool parity
 - keep in mind that the current local `.gms` corpus still exports with no packed event collection,
   so real descriptor mapping needs to stay plumbing-first until better captures exist
 - use `rrt-hook` primarily as optional capture or integration tooling, not as the first execution

docs/runtime-rehost-plan.md

@@ -82,12 +82,16 @@ Implemented today:
   descriptors `230..240`, `241..351`, `352..451`, `453`, and `457..500` now carry recovered
   world-side scalar metadata, while descriptors `454..456` (`All Steam/Diesel/Electric Locos
   Avail.`) now execute as keyed `world_flags`
+- a first-class named locomotive availability runtime surface now exists too:
+  save-slice documents can carry the persisted `[world+0x66b6]` name table into
+  `RuntimeState.named_locomotive_availability`, and imported runtime effects can mutate that map
+  through the ordinary event-service path without requiring Trainbuy or live locomotive-pool parity
 
 That means the next implementation work is breadth, not bootstrap. The recommended next slice is
 broader real grouped-descriptor and ordinary condition-id coverage beyond the current access,
-whole-game toggle, train, player, and numeric-threshold batches. Richer runtime ownership should
+whole-game toggle, train, player, numeric-threshold, and named locomotive availability batches.
-still be added only where a later descriptor or condition family needs more than the current
+Richer runtime ownership should still be added only where a later descriptor or condition family
-event-owned roster.
+needs more than the current event-owned roster.
 
 ## Why This Boundary
 

fixtures/runtime/packed-event-named-locomotive-availability-save-slice-fixture.json

@@ -0,0 +1,60 @@
+{
+  "format_version": 1,
+  "fixture_id": "packed-event-named-locomotive-availability-save-slice-fixture",
+  "source": {
+    "kind": "captured-runtime",
+    "description": "Fixture backed by a tracked save-slice document that imports the named locomotive availability table and mutates it through an imported packed-event record."
+  },
+  "state_save_slice_path": "packed-event-named-locomotive-availability-save-slice.json",
+  "commands": [
+    {
+      "kind": "service_trigger_kind",
+      "trigger_kind": 7
+    }
+  ],
+  "expected_summary": {
+    "calendar_projection_is_placeholder": true,
+    "packed_event_collection_present": true,
+    "packed_event_record_count": 1,
+    "packed_event_decoded_record_count": 1,
+    "packed_event_imported_runtime_record_count": 1,
+    "event_runtime_record_count": 1,
+    "named_locomotive_availability_count": 3,
+    "zero_named_locomotive_availability_count": 2,
+    "total_event_record_service_count": 1,
+    "total_trigger_dispatch_count": 1,
+    "dirty_rerun_count": 0
+  },
+  "expected_state_fragment": {
+    "world_flags": {
+      "save_slice.named_locomotive_availability_present": true
+    },
+    "metadata": {
+      "save_slice.named_locomotive_availability_source_kind": "runtime-save-direct-serializer",
+      "save_slice.named_locomotive_availability_entry_count": "2",
+      "save_slice.named_locomotive_availability_zero_count": "1"
+    },
+    "named_locomotive_availability": {
+      "Big Boy": 0,
+      "GP7": 0,
+      "Mikado": 1
+    },
+    "packed_event_collection": {
+      "live_entry_ids": [
+        17
+      ],
+      "records": [
+        {
+          "decode_status": "executable",
+          "import_outcome": "imported"
+        }
+      ]
+    },
+    "event_runtime_records": [
+      {
+        "record_id": 17,
+        "service_count": 1
+      }
+    ]
+  }
+}

fixtures/runtime/packed-event-named-locomotive-availability-save-slice.json

@@ -0,0 +1,117 @@
+{
+  "format_version": 1,
+  "save_slice_id": "packed-event-named-locomotive-availability-save-slice",
+  "source": {
+    "description": "Tracked save-slice document proving named locomotive availability survives save import and can be mutated by imported packed events.",
+    "original_save_filename": "captured-named-locomotive-availability.gms",
+    "original_save_sha256": "named-locomotive-availability-sample-sha256",
+    "notes": [
+      "tracked as JSON save-slice document rather than raw .smp",
+      "locks the named locomotive availability import surface without guessing per-descriptor locomotive names"
+    ]
+  },
+  "save_slice": {
+    "file_extension_hint": "gms",
+    "container_profile_family": "rt3-classic-save-container-v1",
+    "mechanism_family": "classic-save-rehydrate-v1",
+    "mechanism_confidence": "grounded",
+    "trailer_family": null,
+    "bridge_family": null,
+    "profile": null,
+    "candidate_availability_table": null,
+    "named_locomotive_availability_table": {
+      "source_kind": "runtime-save-direct-serializer",
+      "semantic_family": "scenario-named-locomotive-availability-table",
+      "header_offset": null,
+      "entries_offset": null,
+      "entries_end_offset": null,
+      "observed_entry_count": 2,
+      "zero_availability_count": 1,
+      "zero_availability_names": [
+        "GP7"
+      ],
+      "entries": [
+        {
+          "index": 0,
+          "offset": 0,
+          "text": "Big Boy",
+          "availability_dword": 1,
+          "availability_dword_hex": "0x00000001",
+          "trailer_word": 1,
+          "trailer_word_hex": "0x00000001"
+        },
+        {
+          "index": 1,
+          "offset": 65,
+          "text": "GP7",
+          "availability_dword": 0,
+          "availability_dword_hex": "0x00000000",
+          "trailer_word": 0,
+          "trailer_word_hex": "0x00000000"
+        }
+      ]
+    },
+    "special_conditions_table": null,
+    "event_runtime_collection": {
+      "source_kind": "packed-event-runtime-collection",
+      "mechanism_family": "classic-save-rehydrate-v1",
+      "mechanism_confidence": "grounded",
+      "container_profile_family": "rt3-classic-save-container-v1",
+      "metadata_tag_offset": 28928,
+      "records_tag_offset": 29184,
+      "close_tag_offset": 29440,
+      "packed_state_version": 1001,
+      "packed_state_version_hex": "0x000003e9",
+      "live_id_bound": 17,
+      "live_record_count": 1,
+      "live_entry_ids": [
+        17
+      ],
+      "decoded_record_count": 1,
+      "imported_runtime_record_count": 1,
+      "records": [
+        {
+          "record_index": 0,
+          "live_entry_id": 17,
+          "payload_offset": 29186,
+          "payload_len": 64,
+          "decode_status": "executable",
+          "payload_family": "synthetic_harness",
+          "trigger_kind": 7,
+          "active": true,
+          "marks_collection_dirty": false,
+          "one_shot": false,
+          "text_bands": [],
+          "standalone_condition_row_count": 0,
+          "standalone_condition_rows": [],
+          "grouped_effect_row_counts": [
+            0,
+            0,
+            0,
+            0
+          ],
+          "grouped_effect_rows": [],
+          "decoded_actions": [
+            {
+              "kind": "set_named_locomotive_availability",
+              "name": "Big Boy",
+              "value": false
+            },
+            {
+              "kind": "set_named_locomotive_availability",
+              "name": "Mikado",
+              "value": true
+            }
+          ],
+          "executable_import_ready": true,
+          "notes": [
+            "fixture packed-event record"
+          ]
+        }
+      ]
+    },
+    "notes": [
+      "named locomotive availability import surface"
+    ]
+  }
+}

fixtures/runtime/packed-event-selective-import-overlay-fixture.json

@@ -21,7 +21,7 @@
     },
     "calendar_projection_source": "base-snapshot-preserved",
     "calendar_projection_is_placeholder": false,
-    "world_flag_count": 7,
+    "world_flag_count": 8,
     "company_count": 1,
     "packed_event_collection_present": true,
     "packed_event_record_count": 2,