Problems with tank development were linked to the lack of suitable engine designs and a consequent reliance on available commercial models, and the constraint of the existing railway loading gauge—larger armored vehicles could not be carried on British tracks. It is for this same reason that the Eurostar carriage conforms to British dimensions and is considerably more cramped than Continental carriages.

Philip Mirowski & Dieter Plehwe (eds.), The Road from Mont Pèlerin, loc. 480