Trainspotting is the highest point on the Wither Hills Mountain Bike Park. There are higher bike trails in the Wither Hills Farm Park but you have to cross the fence that marks the boundary of the MTB Park. If you are not a mountain biker, you can reach GZ by taking one of the walking tracks aong a variety of routes towards Jane's Seat. You will need to cross onto the MTB Park over the stock grate.
Last year I placed a couple of caches on the eastern end of the Wither Hills Farm Park while participating in the Marlborough Everest Challenge. This year while doing the challenge again with NZDi, this is our contribution to the geocaching map.
Please take notice of the attributes, you will see there is a Special Tool attribute. The most appropriate special tool in these circumstances is a pair of tweezers or perhaps a sharp pointed pick. The log will be extremely difficult to remove without the special tool.