diff --git a/src/rail_cmd.cpp b/src/rail_cmd.cpp
--- a/src/rail_cmd.cpp
+++ b/src/rail_cmd.cpp
@@ -408,12 +408,8 @@ CommandCost CmdBuildSingleRail(TileIndex
 		}
 
 		case MP_ROAD: {
-#define M(x) (1 << (x))
 			/* Level crossings may only be built on these slopes */
-			if (!HasBit(M(SLOPE_SEN) | M(SLOPE_ENW) | M(SLOPE_NWS) | M(SLOPE_NS) | M(SLOPE_WSE) | M(SLOPE_EW) | M(SLOPE_FLAT), tileh)) {
-				return_cmd_error(STR_ERROR_LAND_SLOPED_IN_WRONG_DIRECTION);
-			}
-#undef M
+			if (!HasBit(VALID_LEVEL_CROSSING_SLOPES, tileh)) return_cmd_error(STR_ERROR_LAND_SLOPED_IN_WRONG_DIRECTION);
 
 			CommandCost ret = EnsureNoVehicleOnGround(tile);
 			if (ret.Failed()) return ret;