Iowa Code § 321.344

1. No person shall operate or move any caterpillar tractor, steam shovel, derrick, roller, or any equipment or structure having a normal operating speed of six or less miles per hour or a vertical body or load clearance of less than nine inches above the level surface of a roadway upon or across any tracks at a railroad grade crossing without first complying with this section.

2. Notice of the intended crossing shall be given to a superintendent of the railroad, and a reasonable time shall be given to the railroad to provide proper protection at the crossing.

3. Before making the crossing, the person operating or moving the vehicle or equipment shall first stop the vehicle or equipment not less than ten feet nor more than fifty feet from the nearest rail of the railroad and, while stopped, shall listen and look in both directions along the track for any approaching railroad train or railroad track equipment and for signals indicating the approach of a railroad train or railroad track equipment, and shall not proceed until the crossing can be made safely.

4. No such crossing shall be made when warning is given by automatic signal or crossing gates or a flagman or otherwise of the immediate approach of a railroad train or railroad track equipment.