Yes it was overground as you can't literally run underground (on the tracks) as you'd kill yourself on the wires.

Therefore, I ran from station to station - worked out the routes before each run and ran with my iPhone and Google Maps and ran to each station on each Underground line. The distance is greatly lengthened because I couldn't run on the tracks but I still visited every station - some as many as 6 times as they appear on 6 different lines.

I had a picture outside of every single one and then went on my way to the next station. I ran over moterways, over footbridges, canals, fields, commuter packed pavements, marsh land, cobbled streets and got lost an awful lot.