| 1995 Stock | |
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| Manufacturer | Alstom |
| In service | 1998-present |
| Lines served | Northern |
| Length per car | 17.77 m |
| Width | 2.63 m |
| Height | 2.875 m |
| Maximum speed | 100 km/h (62mph), limited to 72 km/h (45mph) due to poor infrastructure |
| Weight | DM 29.4 tonnes UNDM 27.9 tonnes T 21.5 tonnes |
| Stock type | Deep-level tube |
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The 1995 Stock used on London Underground's Northern line. There are 106 trains in operation, each of six cars; they entered service between 12 June 1998 and 10 April 2001.[citation needed]
The 1995 Stock shares many features with the 1996 Stock found on the Jubilee line, and indeed both types were built by Alstom in Birmingham. The 1995 and 1996 Stock have different seating layouts and cab designs, and 1996 Stock trains are, at seven cars, one carriage longer. Despite the 1995 Stock designation, the step-plates found on the trains read '1996'. It is believed that the 1995 designation served solely to distinguish this stock from the similarly identified Jubilee line 1996 stock.
It is the only tube stock to use selective door opening. Examples of this can be found at Moorgate and Charing Cross.
The 1995 Stock is operated mainly 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.
Contents |
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 1995 stock uses Alstom's "Onix" three-phase insulated-gate bipolar transistor (IGBT) drive. For comparison, the 1996 stock uses three-phase induction motors fed from a single-source inverter using a gate turn-off thyristor (GTO), derived from those on Class 465 Networker trains.
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 three-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 used on the Jubilee line's 1996 stock achieves this by 'chopping' out short pulses of current. However, modern AC traction such as the 1995 stock uses the IGBT (which is actually an amalgamation of a MOSFET and a conventional transistor), which can switch very large currents very rapidly without damage. In consequence, the 'whine' effect is less noticeable on 1995 stock than on 1996 stock.
One disadvantage of IGBTs is that a higher voltage is dropped across them than other devices (high being about ¾ of a volt). As they conduct several thousand amperes, the resultant power dissipated by the IGBTs requires forced-air cooling. The cooling fans can be heard running and then shutting down when a train draws to a halt.
Since October 2007, the 1995 stock has been fitted with the royal blue seat moquette which is also used on the 1996 and 1973 tube stock trains. The upgrade was completed in early 2008.
Announcer System
The Northern Line is fitted with an automated voice announcer (Celia Drummond). An example of the regular voice pattern is as follows:
- "This station is Clapham Common, this train terminates at High Barnet via Bank."
- "This station is Bank, change here for Docklands Light Railway, Waterloo & City, Circle, Central and District Lines, this train terminates at Edgware."
The Northern Line is unique as it is the only London Underground train to say "Main Line and Suburban Rail Services" at national rail interchange stations, An example of regular voice pattern is as follows:
- "This station is Waterloo, change here for Bakerloo, Jubilee, and Waterloo & City Lines and Main Line and Suburban Rail Services, this train terminates at Kennington.
- "This station is Balham, change here for Main Line Suburban Rail Services, this train terminates at Morden.
The longest voice pattern can be heard at Euston:
- "This station is Euston, Bank branch. Change here for southbound Northern line service via Charing Cross from Platform 6. Victoria Line, and Main Line InterCity and Suburban Rail services. This train terminates at High Barnet."
The voice pattern for closure of the next station is as follows:
- "The next station is closed, this train will not be stopping at the next station." [1]
Maintenance
The Northern Line 1995 Tube stock trains are operated by Tube Lines/LUL, but are provided under a Service Provision contract through Northern Line Service Provision Ltd. (NLSP) which is an Alstom venture. The maintenance of the rolling stock is carried out by Alstom Transport Limited at Golders Green Traincare Centre in North West London situated behind Golders Green tube station and at Morden Traincare Centre in South West London. There are also some "outbases" such as Edgware, High Barnet and Highgate and station fitters based at Kennington and Euston.
Train details
- Length per carriage 17.77 m
- Width per carriage 2.63 m
- Height 2.875 m
- Total seating capacity per six-carriage train 200, plus 20 perch seats and 48 tip-up seats. There are also 24 wheelchair spaces.
- Total passenger capacity per six-carriage train 914
References
- ^ http://www.youtube.com/watch?v=8O-TuEBIjaw Video of clousure of next station on Northern line YouTube.
External links
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Wikimedia Commons has media related to: London Underground 1995 Stock |
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