September 2009 tube map

I used them frequently when I first started as a CSA; having moved up from Dorset specificially to take the job, my knowledge of London outside zone 1 was virtually nil, and my zone 1 information tended to vary in quality depending on whether or not I'd ever previously used that particular station/interchange/part of the line. Having the grid references there on the map made it a lot easier for me to locate stations I was unfamiliar with, and also show the people who were asking about them how to go about using the gridlines to find a station in future.