Can be done as a quick cache'n'dash or as part of a multicach taking walkers on a trip acoss fields and around box common. You are pretty much directly above the London to Bristol Railway line deep in a tunnel below your feet. If you look carefully the nearby house is approriatly named and a nearby drain cover provides access for Network Rail (and is labelled as such).
My Cache trail starts at Rudloe community centre (where free parking is available) and is roughly 3-4km long taking in the following caches:
1 - GC84WBK - If You Go Down To The Woods Today
2 - ######### - Cache Awaiting approval
3 - ######### - Its lovely round here
4 - GC930T6 - View Over Box Tunnel
5 - ######### - The London Line (this cache)
6 - ######### - Boxfields
7 - GC930RQ - Nearly Home