diff --git a/src/core/execution/TrainStationExecution.ts b/src/core/execution/TrainStationExecution.ts
index af8a5bd3f..5f029a0cc 100644
--- a/src/core/execution/TrainStationExecution.ts
+++ b/src/core/execution/TrainStationExecution.ts
@@ -45,7 +45,9 @@ export class TrainStationExecution implements Execution {
       this.active = false;
       return;
     }
-    this.spawnTrain(this.station, ticks);
+    if (this.spawnTrains) {
+      this.spawnTrain(this.station, ticks);
+    }
   }
 
   private shouldSpawnTrain(): boolean {
@@ -69,8 +71,8 @@ export class TrainStationExecution implements Execution {
     if (cluster === null) {
       return;
     }
-    const availableForTrade = cluster.availableForTrade(this.unit.owner());
-    if (availableForTrade.size === 0) {
+    const owner = this.unit.owner();
+    if (!cluster.hasAnyTradeDestination(owner)) {
       return;
     }
     if (!this.shouldSpawnTrain()) {
@@ -79,20 +81,20 @@ export class TrainStationExecution implements Execution {
 
     // Pick a destination randomly.
     // Could be improved to pick a lucrative trip
-    const destination: TrainStation =
-      this.random.randFromSet(availableForTrade);
-    if (destination !== station) {
-      this.mg.addExecution(
-        new TrainExecution(
-          this.mg.railNetwork(),
-          this.unit.owner(),
-          station,
-          destination,
-          this.numCars,
-        ),
-      );
-      this.lastSpawnTick = currentTick;
-    }
+    const destination = cluster.randomTradeDestination(owner, this.random);
+    if (destination === null) return;
+    if (destination === station) return;
+
+    this.mg.addExecution(
+      new TrainExecution(
+        this.mg.railNetwork(),
+        owner,
+        station,
+        destination,
+        this.numCars,
+      ),
+    );
+    this.lastSpawnTick = currentTick;
   }
 
   activeDuringSpawnPhase(): boolean {
diff --git a/src/core/game/TrainStation.ts b/src/core/game/TrainStation.ts
index 9917737d9..6e9b57f0e 100644
--- a/src/core/game/TrainStation.ts
+++ b/src/core/game/TrainStation.ts
@@ -155,6 +155,12 @@ export class TrainStation {
  */
 export class Cluster {
   public stations: Set<TrainStation> = new Set();
+  private tradeStations: Set<TrainStation> = new Set();
+
+  private isTradeStation(station: TrainStation): boolean {
+    const type = station.unit.type();
+    return type === UnitType.City || type === UnitType.Port;
+  }
 
   has(station: TrainStation) {
     return this.stations.has(station);
@@ -162,11 +168,15 @@ export class Cluster {
 
   addStation(station: TrainStation) {
     this.stations.add(station);
+    if (this.isTradeStation(station)) {
+      this.tradeStations.add(station);
+    }
     station.setCluster(this);
   }
 
   removeStation(station: TrainStation) {
     this.stations.delete(station);
+    this.tradeStations.delete(station);
   }
 
   addStations(stations: Set<TrainStation>) {
@@ -181,14 +191,39 @@ export class Cluster {
     }
   }
 
+  hasAnyTradeDestination(player: Player): boolean {
+    for (const station of this.tradeStations) {
+      if (station.tradeAvailable(player)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  randomTradeDestination(
+    player: Player,
+    random: PseudoRandom,
+  ): TrainStation | null {
+    let selected: TrainStation | null = null;
+    let eligibleSeen = 0;
+
+    for (const station of this.tradeStations) {
+      if (!station.tradeAvailable(player)) continue;
+      eligibleSeen++;
+
+      // Reservoir sampling: keep each eligible station with probability 1/eligibleSeen.
+      if (random.nextInt(0, eligibleSeen) === 0) {
+        selected = station;
+      }
+    }
+
+    return selected;
+  }
+
   availableForTrade(player: Player): Set<TrainStation> {
     const tradingStations = new Set<TrainStation>();
-    for (const station of this.stations) {
-      if (
-        (station.unit.type() === UnitType.City ||
-          station.unit.type() === UnitType.Port) &&
-        station.tradeAvailable(player)
-      ) {
+    for (const station of this.tradeStations) {
+      if (station.tradeAvailable(player)) {
         tradingStations.add(station);
       }
     }
@@ -201,6 +236,7 @@ export class Cluster {
 
   clear() {
     this.stations.clear();
+    this.tradeStations.clear();
   }
 }
 
diff --git a/tests/core/game/Cluster.test.ts b/tests/core/game/Cluster.test.ts
index 138e3968e..f64d73d09 100644
--- a/tests/core/game/Cluster.test.ts
+++ b/tests/core/game/Cluster.test.ts
@@ -1,9 +1,13 @@
 import { vi, type Mocked } from "vitest";
+import { UnitType } from "../../../src/core/game/Game";
 import { Cluster, TrainStation } from "../../../src/core/game/TrainStation";
 
 const createMockStation = (id: string): Mocked<TrainStation> => {
   return {
     id,
+    unit: {
+      type: vi.fn(() => UnitType.City),
+    } as any,
     setCluster: vi.fn(),
     getCluster: vi.fn(() => null),
   } as any;
diff --git a/tests/core/game/RailNetwork.test.ts b/tests/core/game/RailNetwork.test.ts
index fc39db81d..70be4febd 100644
--- a/tests/core/game/RailNetwork.test.ts
+++ b/tests/core/game/RailNetwork.test.ts
@@ -1,4 +1,4 @@
-import { Unit } from "../../../src/core/game/Game";
+import { Unit, UnitType } from "../../../src/core/game/Game";
 import {
   RailNetworkImpl,
   StationManagerImpl,
@@ -14,6 +14,7 @@ const createMockStation = (unitId: number): any => {
     unit: {
       id: unitId,
       setTrainStation: vi.fn(),
+      type: vi.fn(() => UnitType.City),
     },
     tile: vi.fn(),
     neighbors: vi.fn(() => []),