London Underground 1992 Stock

The London Underground 1992 Stock is a type of rolling stock used on the Central Line and Waterloo & City Line. A total of 85 eight-car trains were built for the Central Line and 5 four-car trains for the Waterloo & City Line.

 

 

Construction

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The 1992 Stock was constructed by British Rail Engineering Limited (BREL) (under ABB) for the Central line, following extensive testing of three 1986 tube stock prototype trains.

BREL ordered eighty-five 8-car trains, each consisting of four two-car units (two units with driving cabs and the others equipped with shunting controls). Upon entering service in April 1993, the new trains gradually replaced the older 1962 Stock, which was completely withdrawn two years later. These trains were manufactured at the Derby Litchurch Lane Works.

 

 

The original propulsion for the trains was created by a consortium of ABB and Brush Traction and was among the first examples of microprocessor-controlled traction with a fibre-optic network to connect the different control units. The DC traction motors of LT130 type have separately-excited fields and are controlled via GTO (Gate turn-off) thyristors. These would be the only tube trains to use this type of DC motor and would be the last newly built train on the London Underground with DC motors. They were the second to last in the United Kingdom, only succeeded by the Phase 3 MTR Metro Cammell EMUs in Hong Kong, which continued production until the transfer of sovereignty in 1997. These are currently being replaced with more efficient AC motors.

A wheel slide protection (WSP) system had to be retrofitted due to a widespread issue of wheel flats, primarily caused by an excessive number of emergency brake applications during the ATO/ATP testing phases.

The design of the 1992 Stock is reminiscent of the 1986 prototypes. The new 2009 Stock trains, built by Bombardier Transport for the Victoria line, are more similar in shape and design to the 1992 Stock than to the 1995/1996 Stock.

Waterloo & City Line units

After the initial construction run, an additional ten two-car units were built for British Rail for the Waterloo & City line, which at the time was part of the national railway network. These trains were designated as Class 482 until 1 April 1994, when the operation of the line and the trains was transferred to London Underground, and the trains were simply referred to as 1992 Stock. The vehicles are essentially identical to those used on the Central line, with the main difference being the use of trip-cocks for protection instead of ATO/ATP.

 

 

Transport for London and Metronet closed the Waterloo & City line for five months from April to September 2006 to allow major upgrade work on the tunnels and rolling stock. Due to the line's limited access, this was the first time the units had been brought above ground since their introduction 12 years earlier. The refurbishment of the trains saw them painted in the London Underground white, red, and blue livery, replacing the Network SouthEast colors used since the stock's introduction.

Operation

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The 1992 Stock features both automatic train operation (ATO) and automatic train protection (ATP), which effectively allow the trains to drive themselves. The ATO is responsible for operating the train, while the ATP detects electronic codes in the track and feeds them to the cab, displaying the target speed limits. This functionality is configured via a master switch in the driver's cab, which can be set to one of three positions: Automatic, Coded Manual, and Restricted Manual.

Automatic mode

In Automatic mode, both the ATO and ATP are fully operational. The driver is only required to open and close the doors and press a pair of "Start" buttons when the train is ready to depart. The driver then oversees the operation of the system and can intervene at any time. The ATO controls the train to the desired target speed, while the ATP is ready to apply the emergency brakes if the Maximum Safe Speed is exceeded. However, it is not communications-based train control as found on other lines.

 

 

Coded Manual mode

In Coded Manual mode, the ATO is disabled, and the driver operates the train manually. However, the ATP still detects the codes in the track and restricts the driver's actions. The speedometer on the 1992 Stock features a horizontal strip design showing two speeds: the Current Speed in green, indicating the speed at which the train is actually traveling, and the Target Speed, indicating the speed at which the train should be traveling. Although the target speed is always active while running in Automatic or Coded Manual mode, in the latter mode, a change in the target speed is indicated with an upward or downward tone, depending on whether the target speed is increasing or decreasing. Should the driver exceed the target speed, an alarm sounds, and the emergency brakes are automatically applied until the train is below the target speed. For example, if the target speed is 30 mph and the driver is going 35 mph, the emergency brakes will slow the train down to 29 mph.

Restricted Manual mode

In Restricted Manual mode, the train cannot exceed 18 km/h (11.2 mph), and the motors automatically cut out at 16 km/h (9.9 mph). Both the ATO and ATP are disabled, and the driver operates the train entirely by sight and according to the signals. This mode is used when there has been an ATP or signal failure, or in a depot where ATP is not used, such as West Ruislip and Hainault depots. On the main line, driving in ATO is the same for a train driver as driving through a section where signals have failed.

Chancery Lane derailment

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On 25 January 2003, a 1992 Stock train carrying approximately 500 passengers derailed as it entered Chancery Lane station on the westbound line. The derailment resulted in one door being ripped off and several broken windows. Thirty-two passengers sustained minor injuries.

The derailment was caused by the detachment of the rearmost traction motor on the fifth car, due to a gearbox failure. The detached traction motor was struck by the rest of the train as it passed over it, causing the following bogies to derail.

The entire 1992 Stock fleet was withdrawn from service that same afternoon, leading to the closure of the Central and Waterloo & City lines for several weeks until modifications were made. These modifications included fitting new traction-motor bolts and secondary brackets to prevent a loose motor from striking the track and causing further damage. The lines reopened in stages from 14 March 2003.

Refurbishment

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Central Line units

From 2011 to 2012, the Central line 1992 Stock units underwent a refresh of both the interior and exterior. Some of the noticeable changes included the addition of the new "Barman" seat moquette, new brighter interior lighting, and the installation of new window frames. The front of the driving cabs was also refreshed, which included repairing water ingress and replacing a large number of parts with a much simpler design, reducing future maintenance costs and improving the appearance of the front end. The new-style front end can be easily identified by the new red paneling installed on most units, replacing the original grey. This refresh came after nearly twenty years of continuous service on the Central line.

 

 

Since 2019, TfL is doing a major refurbishment on the Central line units as part of the Central Line Improvement Programme (CLIP). This includes a complete overhaul of the interior and adding new features such as new wheelchair spaces, PIS (Passenger Information Screens), and CCTV installed throughout the train. The London Underground corporate livery will also be repainted on these units as well as the replacement of the original DC motors with new AC motors. It takes approximately 10 weeks to refurbish a train. Work started in 2019 but was heavily delayed due to the COVID-19 pandemic, and financial reasons.

 

Waterloo & City Line units

In 2006, the Waterloo & City line was closed for several months to allow for track and signalling upgrade works. During this period, the 1992 Stock units in use on the line were removed by crane from Waterloo depot and taken by road to Wabtec Rail in Doncaster for refurbishment. External changes included repainting the trains, which were still in Network SouthEast livery, into London Underground's corporate livery. Internally, the handrails were repainted from Central line red to Waterloo & City line turquoise, new seat moquette was fitted and CCTV cameras were installed. Later, the units received the new "Barman" moquette fitted to the Central line units, but not the new lighting, window frames or front end.

Future replacement

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In October 2014, it was announced that the 1992 Stock would be replaced by a new semi-articulated model referred to as the New Tube for London (NTfL). This has since slipped to 2025. While a cancellation or deferring was never officially announced, it has been implied that the initial order is now only for replacing the 1973 Stock on the Piccadilly line. TfL still has plans on replacing the 1992 Stock on the Central and Waterloo & City lines as well as the 1972 Stock found on the Bakerloo line with NTfL or a future model, but due to a lack of funding, it has been deferred to an unspecified date further in the future. Should a long-term funding deal with the UK Government be made, this may happen sooner. The refurbishment may have delayed said order.