5 files changed, 31 insertions, 19 deletions

diff --git a/src/rail.h b/src/rail.h
index aaa592da9..68efa0121 100644
--- a/src/rail.h
+++ b/src/rail.h
@@ -300,7 +300,6 @@ static inline Money RailConvertCost(RailType from, RailType to)
 }
 
 void DrawTrainDepotSprite(int x, int y, int image, RailType railtype);
-Vehicle *EnsureNoTrainOnTrackProc(Vehicle *v, void *data);
 int TicksToLeaveDepot(const Train *v);
 
 Foundation GetRailFoundation(Slope tileh, TrackBits bits);
diff --git a/src/rail_cmd.cpp b/src/rail_cmd.cpp
index 439d33b3b..19c044e31 100644
--- a/src/rail_cmd.cpp
+++ b/src/rail_cmd.cpp
@@ -144,32 +144,18 @@ static const byte _track_sloped_sprites[14] = {
  *               11uuuudd => rail depot
  */
 
-
-Vehicle *EnsureNoTrainOnTrackProc(Vehicle *v, void *data)
-{
-	TrackBits rail_bits = *(TrackBits *)data;
-
-	if (v->type != VEH_TRAIN) return NULL;
-
-	Train *t = Train::From(v);
-	if ((t->track != rail_bits) && !TracksOverlap(t->track | rail_bits)) return NULL;
-
-	_error_message = STR_ERROR_TRAIN_IN_THE_WAY + v->type;
-	return v;
-}
-
 /**
  * Tests if a vehicle interacts with the specified track.
- * All track bits interact except parallel TRACK_BIT_HORZ or TRACK_BIT_VERT.
+ * All track bits interact except parallel #TRACK_BIT_HORZ or #TRACK_BIT_VERT.
  *
  * @param tile The tile.
  * @param track The track.
+ * @return \c true if no train that interacts, is found. \c false if a train is found.
  */
 static bool EnsureNoTrainOnTrack(TileIndex tile, Track track)
 {
 	TrackBits rail_bits = TrackToTrackBits(track);
-
-	return !HasVehicleOnPos(tile, &rail_bits, &EnsureNoTrainOnTrackProc);
+	return EnsureNoTrainOnTrackBits(tile, rail_bits);
 }
 
 /** Check that the new track bits may be built.
diff --git a/src/signal.cpp b/src/signal.cpp
index 2eeef336c..778e19c0e 100644
--- a/src/signal.cpp
+++ b/src/signal.cpp
@@ -301,7 +301,7 @@ static SigFlags ExploreSegment(Owner owner)
 
 				if (tracks == TRACK_BIT_HORZ || tracks == TRACK_BIT_VERT) { // there is exactly one incidating track, no need to check
 					tracks = tracks_masked;
-					if (!(flags & SF_TRAIN) && HasVehicleOnPos(tile, &tracks, &EnsureNoTrainOnTrackProc)) flags |= SF_TRAIN;
+					if (!(flags & SF_TRAIN) && !EnsureNoTrainOnTrackBits(tile, tracks)) flags |= SF_TRAIN;
 				} else {
 					if (tracks_masked == TRACK_BIT_NONE) continue; // no incidating track
 					if (!(flags & SF_TRAIN) && HasVehicleOnPos(tile, NULL, &TrainOnTileEnum)) flags |= SF_TRAIN;
diff --git a/src/vehicle.cpp b/src/vehicle.cpp
index 05df6ad9f..440f59bf8 100644
--- a/src/vehicle.cpp
+++ b/src/vehicle.cpp
@@ -452,6 +452,31 @@ CommandCost TunnelBridgeIsFree(TileIndex tile, TileIndex endtile, const Vehicle
 	return CommandCost();
 }
 
+static Vehicle *EnsureNoTrainOnTrackProc(Vehicle *v, void *data)
+{
+	TrackBits rail_bits = *(TrackBits *)data;
+
+	if (v->type != VEH_TRAIN) return NULL;
+
+	Train *t = Train::From(v);
+	if ((t->track != rail_bits) && !TracksOverlap(t->track | rail_bits)) return NULL;
+
+	_error_message = STR_ERROR_TRAIN_IN_THE_WAY + v->type;
+	return v;
+}
+
+/**
+ * Tests if a vehicle interacts with the specified track bits.
+ * All track bits interact except parallel #TRACK_BIT_HORZ or #TRACK_BIT_VERT.
+ *
+ * @param tile The tile.
+ * @param track_bits The track bits.
+ * @return \c true if no train that interacts, is found. \c false if a train is found.
+ */
+bool EnsureNoTrainOnTrackBits(TileIndex tile, TrackBits track_bits)
+{
+	return !HasVehicleOnPos(tile, &track_bits, &EnsureNoTrainOnTrackProc);
+}
 
 static void UpdateNewVehiclePosHash(Vehicle *v, bool remove)
 {
diff --git a/src/vehicle_func.h b/src/vehicle_func.h
index e1e2e2d55..ed9f16e65 100644
--- a/src/vehicle_func.h
+++ b/src/vehicle_func.h
@@ -20,6 +20,7 @@
 #include "transport_type.h"
 #include "newgrf_config.h"
 #include "company_type.h"
+#include "track_type.h"
 
 #define is_custom_sprite(x) (x >= 0xFD)
 #define IS_CUSTOM_FIRSTHEAD_SPRITE(x) (x == 0xFD)
@@ -157,6 +158,7 @@ static inline uint32 GetCmdSendToDepot(const BaseVehicle *v)
 }
 
 CommandCost EnsureNoVehicleOnGround(TileIndex tile);
+bool EnsureNoTrainOnTrackBits(TileIndex tile, TrackBits track_bits);
 void StopAllVehicles();
 
 extern VehicleID _vehicle_id_ctr_day;