An order to buy 30½ 8-car trains of 1967 tube stock was made in March 1964. They were built by Metro-Cammell. Each train is made up of two 4-car units that are joined together. The trains cost £2.25 million to build. Today this would buy just three trains. The first unit was delivered to West Ruislip depot on 27 September 1967, and the fleet was bought to run the Victoria Line. The units were then tested at the depot, before they were moved to Hainault depot and being tried out in passenger service on the Woodford-Hainault shuttle on the Central line. Once the tests were finished, the trains were moved from Hainault to Northumberland Park Depot using a battery locomotive. The trains were looked after at this depot until they were scrapped. It is the only part of the Victoria line that is not Underground, and it is unusual because, unlike the rest of the London Underground network, there is a staff rail link from Seven Sisters station.