If you have a mainline train station near you in the UK, you may be interested to know that you can now use the maps from the Network Rail site (e.g. this one for Birmingham New Street) to start filling out the details inside the station. Of course you could just go to the station and map it out using Mapzen POI collector or Walking Papers, but you're much more likely to be stopped and searched :)
I wrote to Network Rail recently asking if it was okay for us to use the location of points of interest from the maps, and they replied to say they're happy for us to derive that information from the maps as long as we reference where the information came from. I would suggest adding a source = Network Rail tag.