London Underground 1992 Stock

The 1992 Tube Stock is the type of train used on the Central line and Waterloo & City line of the London Underground.

Construction
The 1992 Stock was built by ABB (later Adtranz and now Bombardier Transportation) for the Central line as the result of the extensive testing of the three 1986 tube stock prototype trains. Even so, the introduction of this stock was far from trouble-free and there were many technical teething problems.

Eighty-five trains were ordered from ABB, each formed of four two-car units (two units have driving cabs, the others are fitted with shunting controls). Upon entering service in April 1993, the new units gradually replaced the previous 1962 tube stock, which was finally withdrawn two years later. The trains were manufactured at the former BREL Carriage Works in Derby (Now the Bombardier Derby Carriage and Wagon Works also in Derby which occupies the same site).

The propulsion for the trains was manufactured by a consortium of ABB and Brush Traction, and was one of the first examples of microprocessor controlled traction featuring a network to connect the different control units.

A fault with one of this type of trains that led to the derailment on 25 January 2003. The whole fleet had to be taken out of service for several months, causing the complete withdrawal of services on the Central Line, to permit faulty bolts to be replaced.

The 1992 stock's design is reminiscent of the 1986 prototypes. The new 2009 stock trains, presently being built by Bombardier Transport for the Victoria Line, are more like the 1992 stock in shape and design than the 1995-6 stock.

Due to ongoing problems, the replacement of the DC motors was considered, but decided against. However the 1992 stock may still receive AC motors in the future.

Waterloo & City line
After the initial construction run, an additional ten two-car units were built for British Rail for the Waterloo & City Line, which until 1994 was part of the national railway network, and became their Class 482. When this line passed to London Underground at the start of the process to privatise British Rail on 1 April 1994, these units also passed to London Underground.

TfL 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. The line's limited access meant that this was first time that the units had been brought above ground since their introduction 12 years earlier. The refurbishment of the trains saw them finally painted in the London Underground white, red and blue livery having operated in Network SouthEast colours since the stock's introduction.

Operation
The 1992 stock is one of the few stock types on the London underground to feature both ATO (Automatic Train Operation) and ATP (Automatic Train Protection) which effectively allow the trains to drive themselves. The ATO is responsible for operating the train whilst 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 drivers' cab which can be set to one of three positions: Automatic, Coded Manual & Restricted Manual.

In Automatic Mode the ATO and ATP are both fully operational. The Driver is only required to open and close the doors and press both "Start" buttons when the train is ready to depart.

In Coded Manual Mode, the ATO is disabled and the driver operates the train manually, however the ATP is still detecting the codes in the track and restricting the drivers actions. The speedometer on 1992 stock is the horizontal strip design covering two speeds, the Current Speed in green, indicating the speed the train is travelling at, and the Target Speed indicating the speed the train should be travelling at. Although the target speed is always active whilst running in Automatic or Coded Manual mode, whilst in coded manual, changes in the target speed are indicated with an upwards or downwards 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 within the target speed, the alarm then stops.

In Restricted Manual Mode, the train cannot exceed 18 km/h and the motors automatically cut out at 16 km/h. The ATO and ATP are both 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 failure or a signal failure or in a depot where ATP is not used i.e. 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.

Announcer System
The Central Line is fitted with an automated voice announcer (Emma Clarke) originally (Janet Mayo) and was the first line to receive this facility.

On a Central Line train to Ealing Broadway:

"This is . Please mind the gap between the train and the platform. Change here for the Circle, District, Northern and Waterloo & City Lines, and the DLR. This is a Central Line train to ."

On a Central Line train travelling to Woodford via the Hainault loop:

"This is . Please mind the gap between the train and the platform. Change here for the Jubilee Line, the DLR, and National Rail services. This is a Central Line train to via ."