The pedrail wheel is a type of all-terrain wheel developed in the late 19th and early 20th century by Londoner Bramah Joseph Diplock. It consists of a series of "feet" connected to pivots on a wheel. As the wheel travels, pressure exerted by springs within it increases the number of feet in contact with the ground, thus reducing ground pressure and allowing the wheel to negotiate obstacles and uneven ground.

The development of tanks in World War I was a response to the stalemate that developed on the Western Front. Although vehicles that incorporated the basic principles of the tank had been projected in the decade or so before the War, it was the alarmingly heavy casualties of the start of its trench warfare that stimulated development. Research took place in both Great Britain and France, with Germany only belatedly following the Allies' lead.