Fix road/tram type load check for savegame versions before 62

src/road_map.h

@@ -46,6 +46,24 @@ inline bool MayHaveRoad(TileIndex t)
 	}
 }
 
+/**
+ * Test whether a tile type can have road/tram types.
+ * @param type Tile type.
+ * @return true if tile type can have road/tram types.
+ */
+inline bool MayTileTypeHaveRoad(TileType type)
+{
+	switch (type) {
+		case MP_ROAD:
+		case MP_STATION:
+		case MP_TUNNELBRIDGE:
+			return true;
+
+		default:
+			return false;
+	}
+}
+
 /**
  * Get the type of the road tile.
  * @param t Tile to query.

src/sl/vehicle_sl.cpp

@@ -441,7 +441,12 @@ void AfterLoadVehicles(bool part_of_load)
 					for (RoadVehicle *u = rv; u != nullptr; u = u->Next()) {
 						u->roadtype = rv->roadtype;
 						u->compatible_roadtypes = rv->compatible_roadtypes;
-						if (GetRoadType(u->tile, GetRoadTramType(u->roadtype)) == INVALID_ROADTYPE) is_invalid = true;
+						if (IsSavegameVersionBefore(SLV_62)) {
+							/* Use simplified check before trams were introduced */
+							if (!MayTileTypeHaveRoad(GetTileType(u->tile))) is_invalid = true;
+						} else {
+							if (!MayHaveRoad(u->tile) || GetRoadType(u->tile, GetRoadTramType(u->roadtype)) == INVALID_ROADTYPE) is_invalid = true;
+						}
 					}
 
 					if (is_invalid && part_of_load) {