Help with a lionel cattle car

I believe the arm is a stop for the cattle after they return to the car from the corral.

Burlington route:  DennisB is correct, that black metal arm is a  STOP BAR that holds the cattle in the car for transport when you are done exercising the livestock. In the position of the door now, the bar is across the trough inside the car and will hold back the cattle; when you open the door, the bar is moved toward the end of the car and allows the cattle to travel through the car and eventually out the door on to the cattle pen when activated.

          As regards further work to prep the car for operation:  under the car's trough are several foam cushion (3, I think) which usually get compressed or even lost, as the dry out and the adheasive that was used originally no longer holds them in place.  Look to see that they are there and what shape they are in and if they warrant replacement while you have the car apart.  Parts dealers have these - don't know if you can make your own with a paper hole punch.  Hope this helps, Dennis M.

Cool, so the lever is an on/off switch ... of sorts!

When you say "the foam cushions"...are those the ones under the trough?

 Burlington Route:  Yes, the one's under the trough inside the car.  Dennis M.