Try contacting the company who owns the train ask them if there is space for you to take a portable playpen, and/if they can supply one. Some companies will do this, Take your son everything that comforts him, toys, books, blankey, make him feel safe, this will stop him from being uncomfy and nervous causing him to cry out.When he does get energetic try walking him up and down the train. Show him the scenery, talk to him.It can be an awesome trip for you both if you stay positive.Prepare him, i am imagine you saying what the heck lolTake him on short train rides.Talking to him just enjoying a short ride somewhere.Like adults babies find life scary sometimes, new experiences can be both good and bad.