Fix parking trains, freight deadlock, and Whistle Post lock-in

src/engine/legal.ts

@@ -109,16 +109,12 @@ function localOpsCandidates(s: GameState, player: PlayerIndex): Intent[] {
     if (k?.kind !== 'maneuver' || k.key !== 'flyingSwitch') continue;
     for (const [trayId, tray] of s.trays) {
       if (tray.position.at !== 'grid' || tray.position.owner !== player) continue;
-      const { row, col } = tray.position.coord;
-      const around: GridCoord[] = [
-        { row: row + 1, col },
-        { row: row - 1, col },
-        { row, col: col + 1 },
-        { row, col: col - 1 },
-      ];
-      for (const to of around) {
-        for (let count = 1; count <= tray.consist.length; count++) {
-          out.push({ type: 'maneuver.flyingSwitch', cardId, trayId, count, to });
+      const from = tray.position.coord;
+      for (const reverse of [false, true]) {
+        for (const d of destinationsFor(s, player, trayId, from, reverse)) {
+          for (let count = 1; count <= tray.consist.length; count++) {
+            out.push({ type: 'maneuver.flyingSwitch', cardId, trayId, count, to: d.coord });
+          }
         }
       }
     }