When using a transit directory, the first step in determining which train to take is selecting the county, or counties, in which you are traveling within. Once you have determined that, choose the service provider to transport you to and from your destination.
Upon choosing the service provider (Amtrak, for instance), you have the option to view an entire timetable, as well as a pricing chart, as a guide. For instance, if you want to book a one-way ticket from Baltimore, Maryland, to Washington, D.C., enter the departure and arrival city. This brings up a variety of different times, prices and seating options.