If you blink, you might miss this quirky little coffee shop (coffee nook might be a more appropriate term) near Union Square, but it's worth finding if you like checking out unusual indie coffee shops. This coffee bar share's space with an actual bar - Iron Horse is right inside the front door in a small nook....not tons of counter space, but clearly enough room to make some good coffee! The barista working there when we visited was really friendly and happy to give a sample of the coffee. There's a countertop that runs along the opposite wall with some stools to hang out at for a bit out of the cold. Prices are pretty reasonable for San Francisco, and even if it might not be a big spot you could spend all day in, it's worth the visit to check out this little coffee shop!In the later morning they put out chairs and tables in the street outside -- they were putting them out as we were leaving; on a warmer day with the sun overhead this would probably be a great place to chill for a while (there's free wifi).