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HR2

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On my recent visit to London I had chance to ride on the Central, Jubilee and Northern lines. Now I find it curious that all three stocks with a similar body design and seating layout can sound so different.

The Jubilee has that lovely 'changing gear' sound when accelerating. The northern stuff whines like the old 'R' stock used to and the Central line rubbish rattles and clatters and roars like the crap it is.

What is the difference between the traction control stuff of all three stocks?
 
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Tom

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I can tell you the 95/96 stuff...

The 96TS traction motor has a GTO thyristor which creates that changing gear (although the stock is "newer", it is older in terms of technology, as the design was frozen in 1992 and is based on the Networker).

The 95TS traction motor has an IGBT thyristor which creates the whine.
 

Sturdjos

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I agree with you, DVN! :D

I like the 92s, for what they're worth (which ain't much!)

IMO though, they're a good stock.
 

Met Driver

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92s are fun to ride on, I must admit. However I can't say I'm too keen on the seats - typical ironing board trash if you ask me. The 95s/96s are far better on the comfort front!

Dennis said:
remind me, what's a thyristor and what does it do?

I found a pretty good description over at http://www.railway-technical.com -

A type of diode with a controlling gate which allows current to pass through it when the gate is energised. The gate is closed by the current being applied to the thyristor in the reverse direction. Thyristors (also referred to as choppers) are used for traction power control in place of resistance control systems. A GTO (Gate Turn Off) thyristor is a development in which current is turned off is by applying a pulse of current to the gate.
 

ChrisCooper

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That's actually slighly wrong. Thyristors didn't replace resistance control systems, since a thyristor will only turn off when the power is turned off, which automatically occurs in an AC system when the current reverses. They were used to replace tap changers on both locos and units (the first loco fitted being 87101). GTO thyristors are what were used in DC systems, since they can be turned off aswell as on by a pulse at the gate (hence Gate Turn Off). It's easily possible to tell if a train has normal thyristors or GTO thyristors since thyristors hum wheras GTO thyristors whine (compare the sound of a 317 to a 319, they have pretty much identical motors, but the former has thyristors, and the latter GTO thyristors). Since they can be turned off and on as required, GTO thyristors can also be used to preduce an alternating current of controllable frequency, and these are used on early trains with AC motors. The "gear change" sound is the thyristor changing frequency as the train accelerates or brakes. IGBTs or Insulated Gate Bipolar Transistors are a further development, which allow much faster switching of frequency, so give a smooth sound without the "gear change", and are fitted to all new trains.
Regrading the 1992 tube stock, these have DC motors with GTO thyristor control, which again give a different sound. Various refinements, along with the fact that they are small, fairly low powered motors compared to on the older stock, means they sound quite different, sounding more like IGBT controlled AC motors.
 

Julian G

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the best thing about 95TS- It's sounds like a Desiro arriving, and Celia
the best thing about 96TS- Perch Seats
the best thing about 92TS- The train accelerating

Did someone mention 319?!?! :razz:
 

Julian G

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dvn1357 said:
92stock are just quite simply a tube train! Have they finally got rid of 'Sonia'?
i think so,
i'm now starting to hear Very Loud 'Emma'
 
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