Railroads are made up of freight and/or passenger cars used for transportation on railed tracks. Engines may be of the steam variety popular in the 1800's, or the electric or diesel engines of today. Because steam locomotives have been phased out due to safety and economic reasons, many are preserved in working order by heritage railways and used for filming "period" features.
The interiors of these passenger cars provide the historical set dressing for the film's action. Adding to the cars themselves, the platforms, ticket offices and waiting rooms at train depots make for the perfect movie set.