(svn r16311) -Fix: (Get|Set)TrackBits() is only valid for RAIL_TILE_NORMAL and _SIGNALS.

src/ai/api/ai_rail.cpp

@@ -203,6 +203,7 @@
 	if (IsRailWaypointTile(tile)) return ::GetRailWaypointBits(tile);
 	if (IsRailStationTile(tile)) return ::TrackToTrackBits(::GetRailStationTrack(tile));
 	if (IsLevelCrossingTile(tile)) return ::GetCrossingRailBits(tile);
+	if (IsRailDepotTile(tile)) return ::TRACK_BIT_NONE;
 	return ::GetTrackBits(tile);
 }
 

src/ai/api/ai_rail.hpp

@@ -293,6 +293,7 @@ public:
 
 	/**
 	 * Get all RailTracks on the given tile.
+	 * @note A depot has no railtracks.
 	 * @param tile The tile to check.
 	 * @pre IsRailTile(tile).
 	 * @return A bitmask of RailTrack with all RailTracks on the tile.