This is a mounting block. This is a crossrail.

I read somewhere that racehorses never encounter a mounting block because the jockey is always just given a leg up. When I first brought Bizzy up into the ring, she was cool as a cucumber until, sure enough, she gave a comically startled and shocked reaction to the mounting block. She ducked down, front legs splayed forward, and did a double take. We stood there for a minute and let her blow on it and sniff it until she could place the thing in her consciousness and decide that it wasn’t going to bother her again.

Early on, when we mounted her from it she didn’t know how to stand still. She moved forward and back and sometimes sideways, which doesn’t work. You don’t want a moving target when you’re mounting a horse. But pretty soon she learned, and then it was time to introduce the next big thing: The crossrail.

See below.