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LU SSL 750v upgrade

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Dstock7080

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without finding another suitable thread:

The Four Lines Modernisation (4LM) programme has delivered a first for London Underground (LU).
For the first time on our network, the Metropolitan Line, north of Harrow to Amersham, Watford and Chesham, now operate at 750v. Previously it had operated at 630v like the rest of the network.
Senior Project Manager said: “Switching on the 750v traction power on this part of the Metropolitan Line is a massive achievement as it will enable us to reduce energy consumption and increase the number of trains per hour to 32 once the new signalling upgrade is complete.”
This section of the Metropolitan Line can now operate regenerative braking too. Regenerative braking uses a converter on the train to recycle the energy generated in the braking process so that it can be delivered back to the conductor rail for the next train to use. It will create impressive energy savings, reduce the carbon footprint and maintenance, and increase rolling stock performance.

Lead Project Engineer, said: “This is the single biggest event in LU direct current power history in more than 40 years.”

To migrate from 630v to 750v, a significant amount of work was completed, including reconfiguring the substation transformers. We also needed to ensure the current online relays, fault detection, tunnel lighting systems, passenger trains and engineering trains were compatible with the higher voltage. The mechanism that tells the train to open its doors was also changed.
These enabling works will allow the Sub Surface Lines (SSL) to increase capacity by a third by 2023, which equates to tens of thousands more customers each hour.
The team will migrate further areas of the SSL track to 750v over the next year.
 
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Met Driver

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I had it in my mind that the Vic went up to 750 once DTG-R was fully implemented and the '67s had all gone, but apparently not?.
 

Chris125

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TRV isn't confirmed working on 750V with regen even though battery locos are all done IIRC, and the D78 RAT will be...


Will this be an issue for the A Stock RAT in the meantime?
 
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Nym

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Will this be an issue for the A Stock RAT in the meantime?

The A60 stock has a lot less electronic equipment on board, there's no Static Converter and the electric machines can just have series resistors inserted, so long as the motors are sufficiently rated, there shouldn't be too much of an issue.
 

philthetube

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I am intrigued as to which tunnel lighting systems needed attention, there is only one tunnel and that has no lights, (north curve between Croxley and Rickmansworth)
 

Dstock7080

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The traction voltage on parts the District/Circle/H&C Lines is to be increased to nominal 750vDC (regenerative voltage 890vDC) by the end of June:
- Upminster-Upney
- Barking-Whitechapel
- Tower Hill/Aldgate East-Moorgate
- Tower Hill-Victoria.

As a result of an increase in regenerative voltage in the Earl's Court area, as from 4 June it will not be possible to operate 1973 Tube Stock beyond West Kensington/Lillie Bridge sidings. If a train is to be worked beyond Barons Court EB local permission must be sourced and various equipment must be isolated, cab A/C, all heaters etc.
 
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Nym

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The traction voltage on parts the District/Circle/H&C Lines is to be increased to nominal 750vDC (regenerative voltage 890vDC) by the end of June:
- Upminster-Upney
- Barking-Whitechapel
- Tower Hill/Aldgate East-Moorgate
- Tower Hill-Victoria.

As a result of an increase in regenerative voltage in the Earl's Court area, as from 4 June it will not be possible to operate 1973 Tube Stock beyond West Kensington/Lillie Bridge sidings. If a train is to be worked beyond Barons Court EB local permission must be sourced and various equipment must be isolated, cab A/C, all heaters etc.

I wonder what level of isolation will be needed. Tripping the circuits would work for heaters but possibly not the Static Convertor...
You'd proberbly need to pull fuses to do it.

Moving 1972TS over 750/890 isn't too complex though...
 

gimmea50anyday

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Thought the electrical system was +430/-230 (ish) as opposed to +660-750 as typically found on SR territory to prevent electrolyte leakage in the tunnels? has that changed now or are we talking nominal voltage across the terminals (the +ve and -ve rails in this case)? Does the voltage difference really make that much of a difference in this case as I would have thought the train would simply draw what it needed?

I recall the Liverpool Overhead when they ran on merseyrail tracks for direct aintree services they had to run "series only" due to the voltage difference but I think the voltage difference was much bigger.
 

rebmcr

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Thought the electrical system was +430/-230 (ish) as opposed to +660-750 as typically found on SR territory to prevent electrolyte leakage in the tunnels? has that changed now or are we talking nominal voltage across the terminals (the +ve and -ve rails in this case)?

Yes, it's measured across the terminals. Shared sections with NR do have +0/+750 nominal.

Does the voltage difference really make that much of a difference in this case as I would have thought the train would simply draw what it needed?

Draw is in amps and is independent and varying for each train. Voltage is set by the supply and only varies slightly under regeneration/heavy load.
 

Mojo

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The operational procedures have been revised again since the traffic circular was published and 73 Stocks can not reverse at Lillie Bridge either, now only West Kensington.

You just have to cut out air conditioning and cab/saloon heaters.
 

Nym

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The operational procedures have been revised again since the traffic circular was published and 73 Stocks can not reverse at Lillie Bridge either, now only West Kensington.

You just have to cut out air conditioning and cab/saloon heaters.

And hope the Compressors and MAs don't flash over?
 

Dstock7080

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further to post #7, the Richmond branch (from Chiswick Pk substation gap-Richmond) regenerative voltage will be upgraded from 650v to 890vDC as from Monday 19 June.
 

Dstock7080

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The 750v Sub-surface upgrade has now been completed, all sections;
- Upminster - Putney Bridge/Barons Court/Olympia
- Hammersmith/Finchley Road - Tower Hill/Aldgate East
- Amersham/Chesham/Watford - Harrow.

sections not being done;
- Uxbridge - Harrow (remains at 630v nominal and regen at 650v)
- Harrow - Finchley Road (remains at 630v but regen available at 790v)
- Barons Court - Ealing Bdwy ( remains at 630v and regen at 650v)
 
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edwin_m

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Anyone know wny these sections aren't being upgraded? Does the train need to know where it is to adjust its regeneration on different sections, and if so how?
 

Mojo

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Anyone know wny these sections aren't being upgraded? Does the train need to know where it is to adjust its regeneration on different sections, and if so how?
Uxbridge to Rayners Lane wouldn't be possible in any case as Piccadilly line 1973 stock runs over the line. As for the other sections, not sure.
 

Dstock7080

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Uxbridge to Rayners Lane wouldn't be possible in any case as Piccadilly line 1973 stock runs over the line. As for the other sections, not sure.
Harrow-Finchley Rd for similar reasons with Jubilee ‘96 Stock.
 
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