Fix FindTrainOnTrackEnum finding trains inside signalled bridge/tunnels.

Now only find trains on the given entrance/exit tile.
This fixes trains not leaving stations by PBS into non-empty signalled
bridge/tunnels.

src/pbs.cpp

@@ -275,6 +275,14 @@ static Vehicle *FindTrainOnTrackEnum(Vehicle *v, void *data)
 	if (v->type != VEH_TRAIN || (v->vehstatus & VS_CRASHED)) return NULL;
 
 	Train *t = Train::From(v);
+	if (t->track == TRACK_BIT_WORMHOLE) {
+		/* Do not find trains inside signalled bridge/tunnels.
+		 * Trains on the ramp/entrance itself are found though.
+		 */
+		if (IsTileType(info->res.tile, MP_TUNNELBRIDGE) && HasWormholeSignals(info->res.tile) && info->res.tile != TileVirtXY(t->x_pos, t->y_pos)) {
+			return NULL;
+		}
+	}
 	if (t->track == TRACK_BIT_WORMHOLE || HasBit((TrackBits)t->track, TrackdirToTrack(info->res.trackdir))) {
 		t = t->First();