(svn r22050) -Fix-ish [FS#4496]: in ancient savegames, e.g. TTO savegames, non primary vehicles (wagons and such) could have unitnumbers or even orders. However, these orders would not be updated when a station is removed. As such some savegames have wagons with current orders to invalid stations which triggers trouble in the load conversion. So, trash any orders/unitnumbers a non-primary vehicle has.

src/saveload/vehicle_sl.cpp

@@ -289,6 +289,12 @@ void AfterLoadVehicles(bool part_of_load)
 					}
 				}
 			}
+
+			/* In some old savegames there might be some "crap" stored. */
+			if (IsSavegameVersionBefore(160) && !v->IsPrimaryVehicle()) {
+				v->current_order.Free();
+				v->unitnumber = 0;
+			}
 		}
 	}