London Underground Q Stock

The London Underground Q Stock were trains used on the District Line of the London Underground until 1971. These electric multiple unit trains had air-operated sliding doors and were formed from 1938 onwards from trains built between 1923 and 1935 (originally built with manually-operated sliding doors), plus new purpose-built carriages. The cars were further sub-classified by their original construction date, for example the former G Stock becoming known as Q23 Stock.

Modernisation

The origins of the Q Stock result from the earliest days of electrification of the District Line. The B Stock trains (built from 1905) included poorly constructed wooden trailer carriages which required urgent (and premature replacement), resulting in the construction of new G Stock motor cars in 1923. The steel-undercarriaged B Stock motor cars were largely converted to trailer cars, but also required replacement by the mid 1930s.

The Q Stock project was part of the London Passenger Transport Board's modernisation programme known as the 1935-1940 New Works Programme. The conversion of existing trains to form the Q Stock was a comparatively low cost method of modernising rolling stock which still had many years of operational life left; by combining almost all District Line trains built between 1923 and 1935 into a single fleet greater operational flexibility could result. Additionally, the conversion to air-operated sliding doors was both for greater passenger safety and to reduce delays at stations.

The C Stock, D Stock and E Stock (built 1910-1914) were not capable of conversion to air-operated sliding doors, thus was left out of the Q Stock programme (along with some other 1923-1935 built cars). These hand-operated sliding door cars were then reclassified as H Stock and were progressively withdrawn throughout the 1950s. The F Stock was incompatible with the rest of the District Line fleet and was thus also left out of the Q Stock programme (and was transferred to the Metropolitan Line in the early 1950s).

Composition

The Q Stock consisted of converted trains of:

• G Stock, built in 1923, reclassfied as Q23 Stock
• K Stock, built in 1927, reclassfied as Q27 Stock
• L Stock, built in 1931, reclassfied as Q31 Stock
• M Stock, built in 1935, reclassfied as Q35 Stock
• N Stock, built in 1935, reclassfied as Q35 Stock

plus

• 25 new driving motor cars and 183 new trailer cars of Q38 Stock, built in 1938, with the intention of eventual conversion to R Stock motor cars (which took place from 1947 onwards)

The resulting hybrid composition of carriages produced trains of a very odd appearance, from the flat-sided cleristory roofed earlier carriages to the flare-sided domed roofed Q38 carriages.

Operation

Q Stock provided much of the District Line's rolling stock throughout its life. Q Stock trains were also used on the East London Line following the withdrawal of the F Stock in 1963. Q Stock trains were also occasionally used on the Circle Line, notably on Sundays (partly to keep District Line drivers familiar with the route).

Withdrawal

The conversion of much of the Q38 trailer cars to R Stock motor cars from 1947 onwards marked the first shrinkage in the Q Stock fleet, but this was compensated by the conversion of other hand-operated door carriages to Q Stock. The first major withdrawals (of the earliest Q Stock cars) started in the 1960s, following the transfer of the remaining 1938-built P Stock units from the Metropolitan Line (upon the arrival of the A60 and A62 Stock), plus the cessation of District Line trains to/from Hounslow West in 1964. Major withdrawals took place in 1970 and 1971, with the transfer of CO/CP Stock from the Circle Line and Hammersmith and City Line (released by new trains of C69 Stock). The final Q Stock train ran in 1971. The final Q38 Stock carriages which were converted to R Stock ran in 1983.