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

test/enhancements.test.ts

@@ -189,7 +189,13 @@ describe('Interlocking and Yard Office relieve the Office', () => {
       consist, direction: 'east', position: { at: 'mainline', index: 1 }, movesUsed: 0,
     });
     const ml = s.division.nodes[1];
-    if (ml?.kind === 'mainline') ml.transits.push({ tray: id, stagesRemaining: 1, direction: 'east' });
+    if (ml?.kind === 'mainline') {
+      // Pin the terrain. Mainline types are drawn from the SHUFFLED deck, so deck composition
+      // would otherwise decide this test's outcome — and Double Track / Uncontrolled Siding set
+      // `trainsMayPass`, which legitimately removes the §8.1 bar being asserted here.
+      ml.card = 'plains';
+      ml.transits.push({ tray: id, stagesRemaining: 1, direction: 'east' });
+    }
     s.clock.phase = 'mainline';
     s.movedThisPhase = new Set();
     return id;