London Underground A60 and A62 Stock

The A Stock (also known as the A60 and A62 Stocks^[2]) is the type of train used on the Metropolitan Line of the London Underground. It was built in two batches (A60 and A62) by Cravens of Sheffield in the early 1960s. The trains replaced all the previous stock then used on the Metropolitan Line (such as F Stock, P Stock, T Stock and locomotive hauled carriages). The A Stock started to be replaced by new trains of S Stock from 2010.

The A Stock is currently the oldest type of train in passenger service on London Underground, and the last rolling stock to have independent motoring and braking controls. In addition, it has no PA announcements.

Development and introduction

The core design of the A Stock was formulated by W S Graff-Baker of the London Passenger Transport Board as part of the electrification of the Metropolitan Line from Rickmansworth to Amersham and Chesham under the 1935–1940 New Works Programme.^[3] The project was delayed by the events of World War II and the lack of funds available during the austerity period which followed the war: however, in 1946 two experimental trailers similar in exterior appearance to the production trains were built using underframes of the T Stock. The trailers were scrapped when the trials concluded.^[1]

When the electrification project commenced in 1959, London Transport placed an order for 31 trains of the A60 Stock, which were built by Cravens of Sheffield. The first A Stock units (5004 and 5008) entered passenger service, beginning with the Watford service on 12 June 1961. Twenty-seven trains of the A62 Stock were built in 1962–63 to replace the F and P Stocks on the Uxbridge service. The roll-out was completed by December 1963.^[1]

The trains were designated as the A Stock to mark the electrification of the Metropolitan Line to Amersham. However the A Stock was also used on the former East London Line (then a branch of the Metropolitan Line) between June 1977 to April 1985, May 1987 to 24 March 1995 and from 25 March 1998 until the line's closure for conversion to the London Overground network on 22 December 2007.^[1]

Design

The London Underground A60 and A62 Stocks were mainly designed as a compromise between the needs of longer distance “outer suburban” passengers on the outer reaches of the line and short distance “urban” passengers over part of the heavily used Circle and Hammersmith & City lines. For this reason the trailer cars feature three sets of doors per car.

A distinctive feature of this stock is the use of “tranverse” seating only. As it was designed for journeys which may last over an hour, most of the seating is of the high capacity 3 + 2 arrangement,^[4] oriented across the car's width as opposed to a longitudinal layout, where seats are arranged along the sides of the carriage. In addition, four tip up seats are provided at the rear of the driving motor.^[5] Nevertheless, despite each 8-car train seating 448 passengers,^[6] these trains provided fewer seats than the locomotive-hauled and T stock trains which they replaced: however, the stock provides more seats than the S Stock, which began replacing the A Stock from 31 July 2010. For the convenience of long-distance passengers the A stock is also equipped with luggage racks and umbrella hooks, being the only stock on the system to have these features, commonplace on most National Rail passenger stock.

The A60 and A62 stocks are identical by appearance but the manufacturer of the compressors are different: The compressors fitted to A60 cars are of the Westinghouse DHC 5A type, while A62 cars have the Reavell TBC 38Z type: the different sound of these can act as an identifying feature.

At 2.946 m (9 ft 8.0 in) these are London Underground's widest trains.^[7]

When the trains were refurbished by Adtranz (now Bombardier) Derby between 1993 and 1998, car end windows were installed and the overall livery was revised.^[6] At the time of refurbishment the line on which they ran had a low priority for receiving new trains.^[8]

Operation

A unit of the A stock consists of four cars: two powered driving motors at each end and two non-powered trailers in between. Each unit is further divided into two sets, consisting of a driving motor and trailer which are semi-permanently coupled. The A Stock operates in a two-unit formation of eight cars on the Metropolitan Line, between Aldgate and Amersham, Chesham, Uxbridge and Watford stations.

Until 11 December 2010, a single unit operated on the Chesham branch at off-peak hours, with two two-unit services running directly to or from Aldgate at each peak hour period. Since 12 December 2010, the off-peak single formation was replaced by a half-hourly two-unit service from Baker Street.^[9]

The A stock also operated in a single-unit formation on the East London Line until 22 December 2007 when the line was closed for extension and conversion works.

When built they had a top speed of 70 mph (110 km/h) (World's fastest 4-rail train), and operated at this speed until the late 1990s/early 2000s. They are permitted to travel at no more than 50 mph (80 km/h) to improve reliability. Despite this, these trains are the fastest on the London Underground network. The A Stock is the last rolling stock on the London underground that still feature independent brake and traction control.^[4] The A stock is also the last remaining stock currently on the London Underground not to have an automated public address system.

Other areas of operation

In addition to the Metropolitan line, the A Stock is permitted to traverse the following sections, subject to the following restrictions:^[10]

Destination blinds

As of 24 July 2010, the following stations are listed on the destination blinds of the A60/62 stock:^[11]

Roster

Cars of the A Stock are identified by a four-digit number. The first digit identifies the type of car (driver or trailer) and the last three digits identify the set number (Numbers 000 to 231). The numbering system of the A stock upon introduction were as follows:

In further detail: