 Pairs of locomotives could be operated in multiple, and motors 1 and 3 or 2 and 4 could be selected if there was a failure of the other pair.As built, the vehicles were long, and could pick up power either from a standard four-rail configuration, or the three-rail configuration of the Central London Railway, until it was converted to four rails in 1940.The next batch of seven vehicles were manufactured by R. Y. Pickering and Co Ltd, who were based in Wishaw, Scotland.