(a) 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.
(b) Before making any crossing, the person operating or moving any vehicle or equipment set forth in this section shall first stop the same not less than ten, nor more than 50, feet from the nearest rail of the railway, and while so stopped shall listen and look in both directions along the track for any approaching train and for signals indicating the approach of a train, and shall not proceed until the crossing can be made safely.
(c) No crossing shall be made when warning is given by automatic signal or crossing gates or a flagger or otherwise of the immediate approach of a railroad train or car.
(d) No stop need be made at a crossing on a rail line on which service has been abandoned and where a sign erected in conformance with section 169.06 and bearing the word "Exempt" has been installed, unless directed otherwise by a flagger. The installation or presence of an exempt sign shall not relieve any driver of the duty to use due care.