Shopper's Special NYC subwayBen Gilbert/Business Insider

The New York City subway system is one of the most fascinating curiosities in a city full of mysteries. Miles of underground track shrouded in darkness, littered with abandoned stations and secret passageways — it’s a common object of desire for the urban explorers among us.

And, occasionally, New York City acknowledges the delightful mystery surrounding its 24-hour transportation system. The annual “Holiday Nostalgia” train line, seen above, is a perfect example of this.

The train line, consisting of eight vintage New York subway cars from several different eras, runs for a few weekends each year — from the Sunday after Thanksgiving to the end of the year, only on Sundays. It costs the same $2.75 as any subway ride.

So what’d we do? We got on the train and took a ride, of course! This is what it’s like.