The MTA is running some vintage trains for the holidays on special excursions. Unlike previous rides where the special trains ran once for a extra fare of $20, this year you can ride one of the old R1/9 cars for the price of a regular fare swipe.
The trains will be running on the 6th Avenue line on Sundays from 10AM-4PM. Also the MTA is even putting some vintage buses into service as well. You can catch one on 34th Street in Manhatan and other lines throughout the city. For details on these trips to the past, you can check the MTA website for lines and depature times.