diff --git a/src/rail_cmd.cpp b/src/rail_cmd.cpp
--- a/src/rail_cmd.cpp
+++ b/src/rail_cmd.cpp
@@ -1417,6 +1417,10 @@ CommandCost CmdConvertRail(TileIndex til
 					break;
 				case MP_ROAD:
 					if (!IsLevelCrossing(tile)) continue;
+					if (RailNoLevelCrossings(totype)) {
+						error.MakeError(STR_ERROR_CROSSING_DISALLOWED);
+						continue;
+					}
 					break;
 				case MP_TUNNELBRIDGE:
 					if (GetTunnelBridgeTransportType(tile) != TRANSPORT_RAIL) continue;