Partial cut-away of Sidewinder. I used to have a copy from an early Annual, but alas, now long gone. If someone has a copy to send I'd be most grateful.
Sidewinder (from Wikipedia)
A military walking vehicle which appeared in the 1965 episode "Pit of Peril". It resembles a giant lobster. Powered by an atomic reactor, the four-legged Sidewinder has two mechanical arms at the front which are used to uproot trees and move aside other obstructions. The vehicle is operated by a crew of three from the cabin at the front. At 50 m long and weighing over 500 tonnes, the Sidewinder is slow and lumbering, but is capable of crossing terrain inaccessible to other land vehicles. The vehicle was developed to prevent South African "brush fire" wars from escalating into larger conflicts and is equipped with a significant amount of weaponry. The prototype vehicle fell into an unmapped landfill pit during testing. Due to spontaneous combustion of the rubbish the inside of the pit was extremely hot.