I don't remember the precise timeline, but for a couple of years or so they were checking IDs universally on Amtrak, then they supposedly started doing random checks but it's been a long time since I've had an ID check. It's almost entirely pointless. Generally identity verification is just security theater. And, ultimately, what're you going to do when someone fails to have ID? Well, when I forgot my license once nothing happened. They decided not to throw me off the train at the next stop without any ID. I assume this was pretty standard.
Identity verification is mostly pointless, identity verification after someone has boarded is entirely pointless, and identity verification pre-boarding wouldn't really be compatible with a functioning train network. Also, too, anyone can steal a damn bus and drive it into a crowd (point being there are a lot easier ways to do damage than train-related program activities).
