(svn r14403) -Fix (r14384): The condition was too restrictive.

src/train_cmd.cpp

@@ -1122,7 +1122,7 @@ CommandCost CmdMoveRailVehicle(TileIndex tile, uint32 flags, uint32 p1, uint32 p
 	}
 
 	/* When we move the front vehicle, the second vehicle might need a unitnumber */
-	if (!HasBit(p2, 0) && (IsFreeWagon(src) || IsFrontEngine(src)) && (flags & DC_AUTOREPLACE) == 0) {
+	if (!HasBit(p2, 0) && (IsFreeWagon(src) || (IsFrontEngine(src) && dst == NULL)) && (flags & DC_AUTOREPLACE) == 0) {
 		Vehicle *second = GetNextUnit(src);
 		if (second != NULL && IsTrainEngine(second) && GetFreeUnitNumber(VEH_TRAIN) > _settings_game.vehicle.max_trains) {
 			return_cmd_error(STR_00E1_TOO_MANY_VEHICLES_IN_GAME);