The HS2 cuts through the countryside at various levels, there will be cuttings, viaducts, green tunnels (these are simply huge pipes placed just below ground level and backfilled with earth) as well as the traditional tunnels that are produced by burrowing deeper underground.
Part of the cache description describes the track level as it passes by the cache.
My thanks to grandson Oakley who provided most of the props, he has now moved on to construction games.
Perhaps this series will capture the imagination of fellow cachers who will place more along the route locally to them.
Please park responsibly and carefully at each location.