(svn r3390) -Fix: [autoreplace] fixed issue where autoreplace failed to attach the cars if the front engine was replaced

and the front engine was multiheaded and the first vehicle after it was the rear part of that engine

vehicle.c

@@ -1654,10 +1654,17 @@ static int32 ReplaceVehicle(Vehicle **w, byte flags)
 			new_front = true;
 
 			new_v->current_order = old_v->current_order;
-			if (old_v->type == VEH_Train){
-				// move the entire train to the new engine, including the old engine. It will be sold in a moment anyway
-				if (GetNextVehicle(old_v) != NULL) {
-					DoCommand(0, 0, (new_v->index << 16) | GetNextVehicle(old_v)->index, 1, DC_EXEC, CMD_MOVE_RAIL_VEHICLE);
+			if (old_v->type == VEH_Train && GetNextVehicle(old_v) != NULL){
+				Vehicle *temp_v = GetNextVehicle(old_v);
+
+				// move the entire train to the new engine, excluding the old engine
+				if (IsMultiheaded(old_v) && temp_v == old_v->u.rail.other_multiheaded_part) {
+					// we got front and rear of a multiheaded engine right after each other. We should work with the next in line instead
+					temp_v = GetNextVehicle(temp_v);
+				}
+
+				if (temp_v != NULL) {
+					DoCommand(0, 0, (new_v->index << 16) | temp_v->index, 1, DC_EXEC, CMD_MOVE_RAIL_VEHICLE);
 				}
 			}
 		}