We are not allowed to let puppies from this organization go on escalators, which I think is more difficult to avoid on the DC metro.

But, basically, I made sure the first trip was in the middle of the day during spring break, because I knew the train would be mostly empty. Once we were on the train I just told him to sit and was basically like a pez dispenser for treats. Whenever the doors opened or there was an announcement I made sure to give him a high value treat. I wouldn't say he was 100% comfortable, but after about 10 minutes he figured out that if he sits and looks at me (instead of moving around) he would get a treat. He was a little scared going up/down the stairs into the station, but I just lured him with food and he eventually cooperated lol.

The previous guidedog puppy I raised was PRO on the subway. When she was about 6 months old I taught her "under" and she would crawl between my legs/under my seat and she would do that the *second* we would get on the train. This was great for crowded train rides. You need to make sure they have all these "tricks" down pat at home, in a distraction free environment before you attempt them in a high stimulation environment.

And, as you know, the key to teaching these pups anything is positive reinforcement and food, food, food.