Three of these trains had the cars streamlined, based upon trial with a 1923 Standard Stock Control Trailer built by Metropolitan Cammell.

These were the first tube cars built for London Underground with the motors and control equipment, etc., under the frame, freeing the space behind the cabs for use by passengers.

When an order was placed with Metropolitan Cammell for four six-car trains in 1935, variations of all of these features were included in the designs.

[4] Each motor was rated at 138 horsepower (103 kW), and the car floors sloped upwards at the ends in order to give adequate clearance for the motorised bogies.

The other three systems were new designs, produced by Metropolitan Vickers, General Electric Company, and a collaboration between Crompton Parkinson and Allen West & Co.

A separate electro-pneumatic switch then controlled the transition from series to parallel configuration, and the camshaft moved back to its starting position, as the resistances were removed again.

On the first, two faceplate controllers, driven by 50-volt motors, and an electro-pneumatic camshaft provided 57 notches between rest and full speed.

The General Electric design used a motor-driven camshaft, which made three complete revolutions between rest and full speed, providing 56 notches.

All four systems needed a 50-volt supply, and this was provided by a 5 kW motor generator set, which also powered the car lighting.

Drivers did not like the arrangement, and when it was shown that the streamlining would have little effect until speeds of 80 miles per hour (130 km/h) were reached, the fourth train, which was fitted with control equipment by Metropolitan Vickers, was built with flat ends and conventional cabs, an appearance that was carried forwards to the 1938 Stock.

From there, there were transferred to Ealing Common depot,[10] where staff from the various companies supplying the equipment completed installation and arranged acceptance tests.

A Press day was held at Northfields depot on 17 November 1936, and the "streamlined wonders" received widespread coverage in national newspapers.

[12] The first train to enter passenger carrying service did so on 8 April 1937 on the Piccadilly Line, and the final one followed nearly a year later, on 10 March 1938.

From 26 April 1937, an extra two-car unit was added to the four-car trains at the end of the afternoon service, and the six-car formation ran through the evening peak.

There were significant teething problems with the new equipment, and when the outbreak of World War II made maintenance difficult, the trains were put into storage at Cockfosters depot.

Three of the cars found temporary use as air raid precaution (ARP) shelters, one at Northfields depot, and two at Cockfosters.

In addition to the rebuilding of the bodywork, all of the traction equipment was removed, and a complete rewire of the electrical system was needed.

[citation needed] In 1949, the flat-fronted units were modified to run as two-car shuttle trains, and were to be transferred to the Central Line.

Two trains returned to the Central Line for the opening of the Epping to Ongar service on 18 November 1957, where they were assisted by a three-car unit of 1938 Stock, specially adapted by fitting two compressors to the trailer car.

[17] The third unit, consisting of cars 10011 and 11011, had been moved to Ealing Common depot in early 1957, to be used in a trial of regenerative braking.

The metadyne controllers were being replaced at the time, as they were proving increasingly unreliable, but London Underground still hoped that the system could be used to reduce energy costs.

The 1935 Stock train was fitted with regenerative braking equipment manufactured by British Thomson-Houston, and the substation at Northfields was adapted to cope with the regenerated current.

The trailer cars were fitted with de-icing equipment in 1964,[17] and the units continued to be used on the Epping to Ongar route, until they were withdrawn from passenger service in 1966, when 1962 Stock replaced them.

Motor cars 10010 and 11010 spent some time at Acton Works for preliminary tests, and were then returned to the Ruislip scrap line.