Alternatives to Filming on Trains and Subways
The simplest and cheapest solution is to use stock footage to suggest a train location, and film your actors in close-up so that you can cheat the location.
Another option is to find a train museum, where stationary trains and stations can be your set. The NY Transit Museum is a frequently used location for professional films and tv, but it is expensive. There are other train museums in the tri-set area, so do your research.
June 2020, Jacobs