The London Underground A60 and A62 Stock, commonly referred to as A Stock, was a type of sub-surface rolling stock which operated on the Metropolitan line of the London Underground from 12 June 1961 to 26 September 2012, and on the East London line from 1977 until 22 December 2007, when it closed to be converted into London Overground (except in 1986, when one-man operation conversion of the fleet took place).
The stock was built in two batches (A60 and A62) by Cravens of Sheffield in the early 1960s, and replaced all other trains on the line.
At the time of its withdrawal in September 2012, the stock was the oldest on the Underground, having been in service for over 50 years. It was the only stock to have luggage racks, umbrella hooks and separate power and braking controls, and the last stock not to feature any automated announcements.
Development and introduction
The design was formulated by W. S. Graff-Baker of the London Passenger Transport Board, as part of the electrification of the Metropolitan line from to Amersham and under the 1935–1940 New Works Programme.
Initial plans for a new Metropolitan line fleet proposed 23 eight-car trains to be reformed from the later builds of T Stock in February 1939 by equipping them with air-worked doors, but the start of the Second World War brought the whole scheme to a halt.
Upon revisiting the plans in 1944, construction began on a test car shell, numbered 17000, at Acton Works with features later incorporated into the production fleet, notably the wide body profile and three air-operated sliding double-doorways which were worked by an additional guard in the adjacent coupled coach. As a compromise between efficient practices of slam-door stock and increased room and safety of sliding-door trains, the interior layout featured an unusual central seating aisle with corridors on both sides and a central partition. Overall, the prototype car was mounted on a T Stock trailer underframe and District line type K2 bogies and was painted in London Transport red livery.
Trailer car 17000 was put into service in January 1946, coupled within a T Stock unit. Public reaction was negative, owing to the seats not being abutted to any windows with the side corridors present alongside little protection from the weather as the doors opened adjacent to the seats. Following on from this feedback, a second prototype car of a similar profile (numbered 20000) was constructed and entered service in June 1947, this time with two double-doorways, a central corridor and pairs of side seats. 17000 had its interior rebuilt to match 20000 in November 1949 and was renumbered 17001. The two trailer cars remained permanently coupled until their withdrawal from service in 1953.
A mock-up driving motor car was also constructed at Acton Works in 1950 based on the prototype T Stock cars. It featured circular windows and a rounder body profile, matching that of the 1938 Stock.
With electrification recommencing in 1959, London Transport placed an order with Cravens of Sheffield for 31 four-car trains to replace both T Stock on services to and Rickmansworth, and locomotive-hauled services to destinations north of Rickmansworth. These trains were designated as A Stock to mark the electrification of the Metropolitan line to Amersham. As such, the earlier batch were referred as the A60 Stock. The first units, 5004 and 5008, entered service to Watford in June 1961. London Transport later ordered an additional 27 A62 Stock trains; these were introduced between 1961 and 1963 to replace F and P Stocks on the branch. By December 1963, the roll-out was complete.
Four-car units were also used on the East London line (initially a branch of the Metropolitan line) from 1977 until 2007, when the line closed to become part of the London Overground network, trains traversing empty between New Cross and Neasden Depot.
Operation and refurbishment
To avoid hauling under-utilised carriages, eight-car trains were divided into their component four-car units at the end of the peak hours, with one unit often stabled. At the start of the peak hours, single units would be coupled to create a longer train. Although this practice was discontinued across the Underground network upon the A Stock's introduction, the unique nature of the Metropolitan line prolonged the operation. From June 1962, decouplings were scheduled at Uxbridge, Watford or Rickmansworth in the platforms, and at Amersham in the sidings.
The practice was discontinued after the 1980 summer season; with exception for the Chalfont & Latimer–Chesham shuttle and East London line, which always required four-car units anyway; since it had become an operational nuisance, with uncoupling usually being cancelled during the winter as it was hazardous in leaf-fall and icy conditions. This also greatly simplified subsequent rolling stock modifications to equip controls for one person operation (OPO) since the inner car cabs would not need to be converted. Conversion to OPO took place on the Metropolitan line from 29 September 1986, following modifications to driving cars with new door controls, safety equipment and larger headlights.
Beginning in 1987, overhauls at Neasden depot saw seven A Stock units having their roofs painted in maroon while a further three were painted in red. Some units had names painted on the cab fronts but this was short-lived due to management objections. In 1989 two A Stock units were fitted with different interiors and repainted into corporate liveries to gauge public opinion prior to refurbishment of the entire fleet.
Commencing between 1994 and 1997, the A Stock trains were refurbished by Adtranz at Derby Litchurch Lane Works, which saw new interiors fitted, car end windows installed, new moquette sewn, the corporate livery being applied and suspension improved. At the time of refurbishment, the Metropolitan line had a low priority for receiving new trains. When built it had a top speed of (world's fastest fourth-rail train), but following refurbishment it was restricted to to improve reliability.
Design
The stock was a compromise between the needs of longer-distance "outer suburban" passengers on the outer reaches of the line and short-distance "urban" passengers over the heavily used Circle and Hammersmith & City lines.
A distinctive feature was the use of transverse seating only, which was uncommon on the Underground, designed for journeys which might last over an hour. Most of the seating was of the high-back 2+3 arrangement. Other unusual features also included luggage racks and umbrella hooks, despite their presence on most contemporary British mainline trains.
Four tip-up seats, previously used by guards prior to conversion to one-person operation, were provided at the rear of the driving motor. Despite each 8-car train seating 448 passengers, the A Stock retrospectively provided fewer seats than the locomotive-hauled and T Stock trains that they replaced, but more seats than the S Stock which replaced them.
A60 and A62 Stocks were nearly identical in appearance. The most significant differences were the border around the destination window on A62 motor cars and the make of compressor under the trailer cars: A60 stock used the Westinghouse DHC 5A, A62 cars the Reavell TBC 38Z.
Other areas of operation In addition to the Metropolitan line, A Stock was permitted to traverse the following sections, subject to the following restrictions: Section Passengers permitted Coupled units permitted Notes to and Northfields DepotYesNoWestbound local line only.No access to Siding 7 at Northfields Depot. to NoYes to YesYesNo access to side platforms at Edgware Road.Edgware Road to NoNoSpecific authorization is required to run on this section.Edgware Road to NoNo to High Street Kensington and (via ), including the Cromwell CurveNoYesNo access to the Acton Town, , and sidings. speed limit at three bridges between Acton Town and South Harrow.Embankment to Mansion HouseNoNoJubilee Line tracks between and YesYesNo access to the Wembley Park and West Hampstead sidings.Usage permitted only when ATO is not in use.
Roster
Cars had a four-digit number. The first digit identified the type of car (driver or trailer), the last three digits the set (000 to 231). Sub-typeDriving Motors (DM)Trailers (T)A605000 to 51236000 to 6123A625124 to 52316124 to 6231Citation: In further detail: Renumbered – unit exists, number withdrawn (x23x )Scrapped before 2010PreservedScrapped after the introduction of S stock Rail Adhesion Train (now scrapped) ^ operational DM † Renumbered + Replaced/formed with a renumbered car A60A DMTD DM A DMTD DM A DMTD DM A DMTD DM A DMTD DM A DMTD DM^5000600060015001^5022602260235023^5044604460455045^5066606660675067^^5088608860895089^^5110611061115111^^5002600260035003^5024602460255025^5046604660475047^5068606860695069^5090609060915091^^5112611261135113^^5004600460055005^5026602660275027^5048604860495049^5070607060715071^5092609260935093^^5114611461155115^^5006600660075007^5028†6028† 60295029^5050605060515051^5072607260735073^5094609460955095^^5116+61166117†+5117^†+5008†+6008†6009†5009†^5030603060315031^5052605260535053^5074607460755075^5096609660975097^^5118611861195119^^5010601060115011^5032603260335033^5054605460555055^5076607660775077^5098609860995099^^5120612061215121^+^5012601260135013^5034†+603460355035^5056605660575057^^5078607860795079^5100610061015101^^5122612261235123^^50146014601550155036†60366037†5037†^5058605860595059^^5080608060815081^5102610261035103^^5232+6232+6233+5233^+^5016601660175017^5038603860395039^5060606060615061^^5082608260835083^5104610461055105^^5234+6234+6235+5235^+^5018601860195019^5040604060415041^5062606260635063^^5084608460855085^5106610661075107^ ^5020602060215021^5042604260435043^5064606460655065^^5086608660875087^5108610861095109^ A62A DMTD DM A DMTD DM A DMTD DM A DMTD DM A DMTD DM A DMTD DM^5124612461255125^51426142614351435160616061615161^5178617861795179^5196619661975197^5214621462155215^^51266126612751275144614461455145^5162616261635163^5180618061815181^5198619861995199^5216621662175217^^51286128612951295146614661475147^5164616461655165^5182618261835183^5200620062015201^5218+621862195219^^51306130613151315148614861495149^5166616661675167^5184618461855185^5202620262035203^5220622062215221^^51326132613351335150615061515151^5168616861695169^5186618661875187^5204620462055205^5222622262235223^^51346134613551355152615261535153^51706170617151715188618861895189^5206620662075207^5224622462255225^^51366136613751375154615461555155^5172617261735173^5190619061915191^5208†620862095209†5226622662275227^^51386138613951395156615661575157^5174617461755175^5192619261935193^5210621062115211^5228622862295229^5140614061415141^5158615861595159^5176617661775177^5194619461955195^5212621262135213^5230623062315231^
Renumberings: a. 5034 and 5008 swapped numbers in July 1985; new 5008 and 6008 became set 5234-6234 in September 1994, 5034 preserved at the London Transport Museum depot, Acton. b. set 5009-6009 renumbered 5235-6235 in September 1994. c. set 5028-6028 renumbered 5232-6232 in June 1985. d. 5036 renumbered 5116 in April 1993 (original 5116 scrapped in 1987 – collision at Kilburn, December 1984) e. set 5117-6117 renumbered 5233-6233 in August 1985; set 5037-6037 renumbered 5117-6117 in April 1993. f. 5208 renumbered 5218 in August 1992 (original 5218 scrapped in 1994 – experimental suspension) g. 5209 renumbered 5121 in March 1993 (original 5121 scrapped in 1994 – collision at Neasden depot, October 1986) Converted works vehicles: s. Sandite dispenser car. Withdrawals: 1. 2.
Withdrawal
The A Stock fleet reached 50 years of service on 12 June 2011. The age of the stock made spare parts more difficult to obtain and vehicles had to be cannibalised to keep the rest of the stock in operation.