London Underground 1996 Stock

Infobox Underground stock


name=1996 Stock
InService=1997-present
Manufacturer=GEC-Alstom
LinesServed=Jubilee
CarLength=17.77m
CarWidth=2.629m
CarHeight=2.875m
MaxSpeed=100 km/h (62 mph)
Weight=DM 30.0 tonnes
UNDM 27.1 tonnes
T 20.9 tonnes
TubeStock=true

The fleet of 1996 Stock running on the London Underground's Jubilee Line is currently the most modern on the network. It is also the fastest, reaching the highest peak speeds of any line on the London Underground network.

There is a degree of confusion with regard to the manufacture and delivery of the Jubilee Line and London Underground's Northern Line 1995 Stock. The development programmes for both stocks was run in parallel, with detail design work undertaken by Alstom in the UK at their Birmingham and Rugby facilities, with the first six train sets manufactured in Alstom's Barcelona factory to the 1996 Stock Jubilee Line design. All type approvals for the design were conducted on these early train sets. The production of the 1995 Stock for the Northern Line subsequently followed from the factory in Barcelona. The balance of the 1996 Stock for the Jubilee Line followed the 1995 Stock Production. Both stocks were freighted to Alstom's facility at Washwood Heath in Birmingham for final assembly and equipping, with 1995 and 1996 stock assembled in adjacent production lines.

The 1996 Stock was bought to support the opening of the Jubilee Line Extension (JLE), which runs from Green Park to Stratford. However, delays in the JLE's opening meant that 1996 Stock was introduced, completely replacing the existing fleet of 1983 Stock, between Christmas Eve 1997 and July 1998 - over a year before the JLE was opened. The existing trains (1983 stock) were originally planned to be refurbished with the same exterior and interior as the new stock (1996 stock) even with double doors, but the cost proved prohibitive.

The 1996 Stock and the similar 1995 Stock found on the Northern Line have different interiors, seating layouts and cab designs designed by Warwick Design Consultants. Other differences include different traction packages (Alstom ONIX system on 1995 Northern Line stock), Train Management Systems, slight differences with Tripcock geometry and the use of LED bodyside lights on the 1995 Northern Line Tubestock while 1996 Tubestock uses filament bulbs. The most apparent difference between the two stocks is the bogie. The Jubilee stock utilises an Alstom bogie with rubber suspension whereas the Northern Line has fitted ADTRANZ [Bombardier] bogies with air suspension to cope with the adruous track conditions encountered on the deepest and longest underground line on the network. The main technical differences occurred because the Jubilee Line 1996 Tubestock was designed as "Cheapest first cost" for LUL, while the 1995 Northern Line Tubestock was designed for "Life Cycle Cost" as Alstom had won the contract to act as service provider and maintainer of this stock. Alstom subsequently won the maintenance of the Jubilee Line 1996 stock to be carried out at the newly constructed Stratford Market depot in East London.

The 1996 Stock is operated with a dead man's handle at the driver's right hand. When the train is stopped the top of the handle is turned away from the position in which the driver holds it. To depart the driver turns the top of the handle and pushes the red lever forward. The trains were originally designed for automatic train operation as on the Victoria and Central Lines, using a Westinghouse system, however, due to operational problems with the system and the cost of upgrading the signalling lineside infrastructure, this system will never enter service. A new system based on the Alcatel SelTrac as used on the DLR [Docklands Light Railway] is currently being installed across the fleet and will be in service by 2009. This is the first application of this system on an underground mass transit line and is referred to as Transmission-Based Train Control [TBTC] . This is a 'moving block' system that will allow trains to run faster and closer together without compromising safety, and is crucial to allow Tube Lines to meet future timetable and passenger loading targets.

The original seat covers were a mauve and grey moqette. They formed the letter 'J' for Jubilee (also the Northern Line's moquete forms the letter 'N') during November 2005 the old cars were refurbished and these seat covers were replaced with the new dark blue Tube Lines moquette. This features multi-coloured and multi-size hollow squares. The new cars were ordered with this moquette. The Piccadilly Line's 1973 Stock also has this moquette, and it has also now been introduced on the Northern Line stock. The armrests were purple but have been repainted blue to match the new seat covers. However, the new (mark 2) trains delivered in late 2005 were still carrying the old internal layout as of March 2008.

The 1996 Stock at the time of commissioning comprised two three car units. Each unit consists of a Driven Motor car [DM] , Trailer car [T] , Unmanned Non-Driven Motor car [UNDM] . A standard train formation would be DM-T-UNDM-UNDM-T-DM. Twelve of the later build trailer cars had de-icing equipment installed and are referred to as De-Icing Trailer cars [DIT] .The trains are numbered with both 'odd' and 'even' ends. The number comprises five digits. The first two digits are the stock type [96] . The third digit refers to the car type: 0 or 1 DM, 2 or 3 T, 4 or 5 UNDM. 7 indicates a DIT. For example, a six car train set would be 96001, 96201, 96401, 96402, 96202, 96002.In the design, each car is given a letter designation. The even cab end car is A, odd cab end car is B, even UNDM is C, odd UNDM is D, trailer cars are E, DIT is F.

Addition of seventh car

During early 2005 London Underground announced that it would be adding a seventh car to the trains of the existing Jubilee Line fleet, and also adding four new complete trains. With the original factory having been closed on the Barcelona beach front, the four new train sets and sixty three new trailer cars were manufactured in Alstom's new factory at Santa Perpetua de Mogoda in the Barcelona suburbs. An interesting fact is that the four new trains were built as six-car trains and modified at the Stratford Depot maintenance facility to the seven car configuration.

So from December 25, 2005, the line was closed for completion of the seventh-car conversion, including signalling alterations and software modification to the platform edge doors on the JLE. The original plan was to hot-wire two cars so that the onboard computer would 'see' them as one car, but this proved not to be necessary. Since the 1996 Stock had been designed as a seven-car train set with the seventh car to be added at a later date, the platforms were already long enough for seven-car trains throughout the line, and the JLE platform edge doors had been built with space for a seventh car. The line was scheduled to close for five days, but the work by Alstom and Tube Lines was completed ahead of schedule, enabling the line to re-open two days early. The new carriage is a trailer car in the 'odd' unit with design designation 'G'.An example of a seven car train set would be 96118, 96318, 96718, 96418,, 96419, 96219, 96119. [seventh car in bold] The above trainset is in fact the first of the new build trains.

There were various differences between the new and old cars at the time of introduction:
* Amber Passenger information displays (PIDs) instead of red
* Black vestibule floor instead of grey
* Yellow strip on door seal
* Better fitted seat covers
* The ridged vestibule floor extends the width of the carMany of these are likely to change as the old cars undergo refurbishment. The new trailer cars are numbered 96601 to 96725 (odd numbers only). The door seal on the new cars still states '1996', because of the national production rules. However the feature the newer Alstom logo, instead of GEC Alstom.

The refurbishment design was carried out by Warwick Design Consultants who also designed the moquette. They were also responsible for the Northern and Picacdilly line refurbishment designs including the driver's cabs and controls.

Following the introduction, an upgrade to the passenger information system has been introduced, resulting in next station announcements playing on approach to stations.

Dot matrix system - Charing Cross

The dot matrix systems in all of the 1996 stock trains still have destination: 'Charing Cross' - and very rarely, trains display: Destination : Charing Cross by mistake. This was in fact recorded once in April and is on YouTube

Announcer System

The Jubilee Line is fitted with a digital voice announcer and dot matrix display, although the two's contents are slightly unrelated.

An example of the regular voice pattern is as follows:"This station is Canary Wharf. Change here for the DLR." "This train terminates at Stratford."

The regular dot matrix pattern at the same station as follows:"Canary Wharf. Change for DLR." "Destination : Stratford."

The voice announcer currently uses two different voices in its standard announcements. The "Next Station" and "This Station" announcements are not the original voice, however the "This Train Terminates At..." announcement is, meaning that at every station two different voices are heard. In addition to this, there is a male announcer (the only London Underground line to have one) who alerts passengers of certain messages such as "This train will now terminate here. All change please" and "Please keep your personal belongings with you, at all times".

Traction control

1995 stock and 1996 stock have similar bodyshells and were both built by Alstom. However, they use different AC traction control systems. The control system on the 1995 stock is more modern than the 1996 stock, reflecting the fact that the latter's design spec was 'frozen' in 1991.

The 1996 stock uses three-phase induction motors fed from a single-source inverter using a GTO (gate-turn-off) thyristor, derived from those on Class 465 Networker trains. The 1995 stock, for comparison, uses Alstom's "Onix" three-phase Insulated Gate Bipolar Transistor drive. [http://www.tfl.gov.uk/tube/foi/pdf/rolling-stock-info.pdf] .

Earlier London Underground stock, like most electric trains until the 1990s, used DC motors. These are now regarded as inefficient, partly because they are traditionally controlled by resistors, and partly because a 3-phase AC induction motor can provide the same power at less size and mass.

However, in an AC motor, maximum torque can only be achieved when the resistance of the rotor windings equals the reactance. AC motors in an industrial setting tend to be operated more or less continuously and therefore large banks of resistors can be used on start-up to raise resistance and maintain torque. This would not be efficient in a small motor designed for stop/start operation.

As a result, it was only the invention of electronic control systems from the 1980s onwards that made AC traction viable for trains. The motor can be supplied using an inverter, and by varying the inverter's output frequency it is possible to keep the frequency of the currents flowing in the rotor windings constant, and hence the reactance (while resistance remains fixed).

The GTO thyristor used on 1996 stock achieves this by 'chopping' out short pulses of current, creating the characteristic audible whine associated with the stock and with the Class 465 networker trains that share its traction control system. The noise timbre changes as the pulse length changes. The noise is produced by the oxygen in the air vibrating as the magnetic field changes (oxygen is magneticFact|date=February 2008 whereas nitrogen is not).

Modern AC traction, such as the 1995 stock, uses the IGBT (which is actually an amalgamation of a MOSFET and a transistor), which can switch very large currents very rapidly without damage. The 'whine' effect is far less noticeable.

Criticisms

The 1996 stock which is now being used on the Jubilee Line has attracted criticisms in that the interior space is extremely small compared to trains on other lines such as the District Line. The Jubilee line serving a vast population in the East London/Stratford area has a huge passenger volume, however the small trains dismayed most Londoners. However, the reason for this is because it is, along with all deep underground lines, of the 'Tube Stock' gauge rather than the larger 'Sub Surface' gauge. This is a historic issue which dates back to the original underground construction methods. Tube Stock includes the Jubilee, Northern, Central, Bakerloo, Waterloo, Victoria and Piccadilly lines. Sub Surface stock run on the Circle, District, Hammersmith & City, Metropolitan and East London lines.

The 1996 stock has also attracted criticism due to the distinctive "whine" described in the section on traction (above), heard when pulling into and out of stations.

Notes

External links

* [http://www.tfl.gov.uk/tube/using/useful-info/technical/rolling/1996.asp 1996 Tube Stock specifications (TfL)]
* [http://www.squarewheels.org.uk/rly/stock/1996tubeStock/ 1996 Tube Stock - Squarewheels.org.uk]
* [http://www.warwickdesign.com Warwick Design Consultants]