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

src/engine/advance.ts

@@ -356,6 +356,7 @@ function enterMainline(
     carriesPassengers,
     node.modifiers ?? [],
     tray.direction,
+    node.gradeUp ?? 'east',
   );
   node.transits.push({ tray: id, stagesRemaining: stages, direction: tray.direction });
   tray.position = { at: 'mainline', index };