diff --git a/train_cmd.c b/train_cmd.c
--- a/train_cmd.c
+++ b/train_cmd.c
@@ -2627,9 +2627,9 @@ static bool CheckCompatibleRail(const Ve
 				Slope tileh = GetTileSlope(tile, &height);
 
 				// correct Z position of a train going under a bridge on slopes
-				if (CorrectZ(tileh)) height += TILE_HEIGHT;
-
-				if (v->z_pos != height) return true; // train is going over bridge
+				if (tileh != SLOPE_FLAT) height += TILE_HEIGHT;
+
+				if (v->z_pos > height) return true; // train is going over bridge
 			}
 			break;