Grain Train Shuttle Operation, NSW Aus

Looks like a grain train shuttle operation. Like those little roofs at the car ends, wonder what they are for? Nice track as well, for a rural operation that train moves pretty fast.

https://www.youtube.com/watch?v=azAIWvQkEUM

If that 90 sigh was a speed sign fot the curve and was in metric, it would be 55 mph. Nice operation in my opinion.

Wonder if they are to protect the air resevior/brake equipment from overfill in a moving loading operation.

At about 6:05, as the train starts moving, next to the rectangular and diamond-shaped signs there is a little sign or signal or something that keeps popping up and down. What is that?

(edit): Judging by its location it seems to have something to do with the switch.

I hope I’m wrong, but it looks like an unsecured switch throw lever…