It is very unlikely that a large national train company wouldn't have TOS for the info on its website. Have a closer look. It may be in a non-obvious place.

If its TOS is something like Amtrak's, the company may still not have a successful suit against you. Amtrak's TOS require the user to recognize that Amtrak's proprietary right in the data on its website is valid and enforceable probably because the law does not recognize that right by default. I think it is written that way to allow Amtrak's attorneys to make some creative arguments in court if it would need to sue. But to win they would probably need to convince a judge to change the law. Having said that, the company could still sue if it really doesn't want you to provide the app in the hope that you settle before the case reaches trial.

Do consult a lawyer just to get a sense of the likely risk of lawsuit.