Totley Tunnel is a 6,230-yard (3.5 mi; 5.7 km) tunnel. It was completed in 1893 and was the longest mainline railway tunnel within the United Kingdom that ran under land for its entire length, until the eastern London tunnel of High Speed 1, which now holds this title. It is therefore the longest non-electrified tunnel in England.
The cache is located on the main road at the top of the station approach and therefore if you intend to bring children please keep a firm grip on them. Cars regularly exceed the speed limit around here. Plenty of off road parking can be found on the station approach
Your looking for a cache just larger than a nano
To see the station complete with tunnel just walk or drive down the station approach which is were most cars park up , there is also a nice cafe at the station when its open
There are a few nice National Trust caches located in the area which makes parking here a good option for a round walk