However, you probably won't arrive at this cache by train!
The Cholsey and Wallingford Railway (CWR) is a preserved former Great Western Railway branchline. The line links the national railway network at Cholsey with the historic market town of Wallingford, Oxfordshire.
Known locally as "The Bunk", passenger services ceased in 1959 but thanks to the CWR Preservation Society trains now run on selected weekends and bank holidays throughout the year. Where available the trains are steam hauled but there is also a fleet of 08 class diesel locomotives. For more information, and for details of the operating schedule, please see the CWR website.
And now for the cache.... Gather the following information from the area around the entrance to the CWR (at the posted coordinates):
1) The number of brown framed noticeboards outside the entrance = A
2) The numbers on the "H" sign attached to a nearby lampost = BCD (top row) and EF (bottom row)
3) The last digit of the phone number on the Southern Gas Networks box = G
The cache can be found at: N51°35.(G-B)(G-E)(A/2) W001°08.(B+E)(G-F)B