Index: rail_cmd.c
===================================================================
--- rail_cmd.c	(r‚vision 4703)
+++ rail_cmd.c	(copie de travail)
@@ -1493,9 +1493,13 @@
 {
 	const SignalVehicleCheckStruct* dest = data;
 	TileIndex tile;
+	TrackdirBits depotbits[] = {TRACKDIR_BIT_X_NE, TRACKDIR_BIT_Y_SE, TRACKDIR_BIT_X_SW, TRACKDIR_BIT_Y_NW};
 
 	if (v->type != VEH_Train) return NULL;
 
+	/* The "signal update" procedure entered the depot from the wrong side */
+	if (IsTileDepotType(dest->tile, TRANSPORT_RAIL) && dest->track == depotbits[GetRailDepotDirection(dest->tile)]) return NULL;
+
 	/* Find the tile outside the tunnel, for signalling */
 	if (v->u.rail.track == 0x40) {
 		tile = GetVehicleOutOfTunnelTile(v);