I look at this photo and I see a toe step. In the lower white painted part of this locomotive, below and behind the numberboard, is a piece of angle iron bolted to the side of the cab. Also visible in the white painted part above and behind the numberboard is a grab iron. As the maintenance person sent out to clean the windshield, your job was to ascent part-way to the cab, put your toes onto this step, grab the grab iron and shinny your way to the grab irons that ascended to the nose (directly behind the numberboard) and clean the windshield with whatever cleaning equipment you carried with you while you transversed the toe step. The CB&Q had this same arrangement, but on the other (fireman's) side.