I had some discussions with Stan Grace, the last owner of Grace Tank Car Lines, a family-owned Chicago-based lessor of tank cars and used equipment dealer founded by his grandfather in
the early teens.
Stan recounted that many tank cars had only one footboard at the dome (and some had none at all) and that was the source of a number of injuries and subsequent lawsuits from railroad
and shipper/receiver workers. Eventulally the ARA rules were changed to require cars to be built with dual footboards and I don't know if the older cars were required to have them added.
The interior shots may illustrate the reason why the worker was going onto the car (to inspect or repair the steam coils??) as there would be no reason to climb on the car to connect the steam
line.
Charlie Vlk