SSR 750v Voltage Upgrade

[spsmiler]

Is the SSR voltage upgrade to 750v still underway?

I remember reading about it going to happen, but at first there was a need to see the back of the A Stock.

Apart from the leaf-fall trains these have now gone, so has it began - or is it still waiting for the D stock leaf fall trains to replace the A stocks?

Also, whereas the 630V dc was actually+420V DC and -210V DC, with the higher voltage will it be +500V DC and -250V DC?

Simon

[Deleted]

Remember the D stock already runs on the higher voltage when they go down the Richmond and Wimbledon branches so dont see them being a problem

[brigham]

Do the Richmond and Wimbledon D-stock trains run on series notches only, when on 'other' metals, like LOR stock to Aintree on race days?

[Colin]

We do not drive D stock any differently on National Rail metals.

As stated, D stock are quite capable of handling 750 volts as a matter of routine.

[spsmiler]

Sorry folks, I was not asking specifically about the D stock.

My query was about the SSR in general - and whether it is still energised at 660v or if this has now been raised to 750v.

By way of a diversion however, re: the D Stock and also the former C stock, its my understanding that right from the outset their electrics were designed to be capable of safely handling as much as 900v, as the natural voltage variables of the mainline power supply system means that the third rail does sometimes get that 'hot'.

Also, for reasons which I do not fully understand it is SWT trains which are restricted in power consumption when between East Putney and Wimbledon.

Simon

[Deleted]

BTW LUL traction voltage is 630v DC not 660v

[Colin]

Mar 17, 2015 20:23:33 GMT spsmiler said:

Sorry folks, I was not asking specifically about the D stock.

My query was about the SSR in general - and whether it is still energised at 660v or if this has now been raised to 750v.

As an operational member of staff, I can confirm that we have not been told traction current has increased beyond 630v; so as far as I and my colleagues are concerned, it is still 630v.

All I can add is there's obvious work taking place at most sub stations along the District line - on that basis I would suggest the power upgrade hasn't yet taken place.

Mar 17, 2015 20:23:33 GMT spsmiler said:

Also, for reasons which I do not fully understand it is SWT trains which are restricted in power consumption when between East Putney and Wimbledon.

Simon

I'm no electrician but I would suggest the reason SWT rolling stock is restricted is probably due to the number of LU trains also present and drawing power at the same time - if enough LU trains draw power on the same section on LU metals, traction current will drop out owing to overload protection, so I reckon its to prevent the same issue.

[North End]

Mar 17, 2015 20:23:33 GMT spsmiler said:

Sorry folks, I was not asking specifically about the D stock.

My query was about the SSR in general - and whether it is still energised at 660v or if this has now been raised to 750v.

By way of a diversion however, re: the D Stock and also the former C stock, its my understanding that right from the outset their electrics were designed to be capable of safely handling as much as 900v, as the natural voltage variables of the mainline power supply system means that the third rail does sometimes get that 'hot'.

Also, for reasons which I do not fully understand it is SWT trains which are restricted in power consumption when between East Putney and Wimbledon.

Simon

I don't believe the SSR has been uplifted at present.

Regarding the Network Rail sections. This may be out of date, but it certainly used to be the case that the sections of the SW Division inwards of Richmond and Wimbledon do not have a line voltage greater than 660v because of the presence of LUL trains. The line voltage then progressively increases on a substation-by-substation basis outwards of those locations.

I'm unsure how the Waterloo & City Line and Euston-Watford stand in this regard.

Certainly this was enough of an issue that Network Rail had a project called something like "Separation of LUL supplies". I'm unsure if this project has progressed beyond the drawing board.

[North End]

Mar 18, 2015 15:17:14 GMT Colin said:

Mar 17, 2015 20:23:33 GMT spsmiler said:

Sorry folks, I was not asking specifically about the D stock.

My query was about the SSR in general - and whether it is still energised at 660v or if this has now been raised to 750v.

As an operational member of staff, I can confirm that we have not been told traction current has increased beyond 630v; so as far as I and my colleagues are concerned, it is still 630v.

All I can add is there's obvious work taking place at most sub stations along the District line - on that basis I would suggest the power upgrade hasn't yet taken place.

Mar 17, 2015 20:23:33 GMT spsmiler said:

Also, for reasons which I do not fully understand it is SWT trains which are restricted in power consumption when between East Putney and Wimbledon.

Simon

I'm no electrician but I would suggest the reason SWT rolling stock is restricted is probably due to the number of LU trains also present and drawing power at the same time - if enough LU trains draw power on the same section on LU metals, traction current will drop out owing to overload protection, so I reckon its to prevent the same issue.

The Northern Line has recently developed the superb spectacle in the Stockwell area that at peak times on certain days, move the handle to full motors and the tunnel lights come on, shut off and they go off!

On the subject of the Wimbledon branch, the restrictions are a little strange, as the SA shows classes 450 and 458 as restricted, but not class 444.

[bigvern]

When we have run to Uxbridge with the AIT, track voltage at Uxbridge was recorded as being up at 736v, but voltage does fluctuate, and depends on the Sub stations and feeding arrangements and train movements , Staff are trained that is 630v but this is a nominal figure, and for that purpose it dosent really matter other that it treated as high voltage.

[roythebus]

The higher voltages on the Wimbledon and Richmond branches are the reason for the neutral sections on Putney Bridge and at Gunnersbury. In my day on the Underground we were told that the branch voltages could be higher. It was all high voltage, so don't touch it!

Again, there was no restriction on BR stock taking full power on either branch, but that was back in the 1970's.

[Deleted]

MAR's (as used in 73ts and 78ts) are tested at 500V, 600V and 750V due to the voltage varying on the network.

[bassmike]

The neutral sections on Putney Bridge and Gunnersbury are not for voltage levels ,but for the changeover from 3 to 4 rail and v/v. From the middle of P.B it changes to earthed centre rail with a neutral section (when lights go off and on. Similar arr: at G'bury a few yards up the District branch.

[roythebus]

Correct.

[Deleted]

Mar 19, 2015 0:56:18 GMT North End said:

Mar 18, 2015 15:17:14 GMT Colin said:

As an operational member of staff, I can confirm that we have not been told traction current has increased beyond 630v; so as far as I and my colleagues are concerned, it is still 630v.

All I can add is there's obvious work taking place at most sub stations along the District line - on that basis I would suggest the power upgrade hasn't yet taken place.

I'm no electrician but I would suggest the reason SWT rolling stock is restricted is probably due to the number of LU trains also present and drawing power at the same time - if enough LU trains draw power on the same section on LU metals, traction current will drop out owing to overload protection, so I reckon its to prevent the same issue.

The Northern Line has recently developed the superb spectacle in the Stockwell area that at peak times on certain days, move the handle to full motors and the tunnel lights come on, shut off and they go off!

On the subject of the Wimbledon branch, the restrictions are a little strange, as the SA shows classes 450 and 458 as restricted, but not class 444.

As far as I'm aware class 444s are already restricted in power which is why they may not be restricted the way 450s and 458s are.

[Deleted]

The Class 501's went from 630 V to 750V without problems as is evidenced by the number of them that worked on the Southern on departmental dukes and the 501 Farewell tour that traversed a quite a bit of the Southern as well!

[bassmike]

yes, I was on that tour I think it got as far as Horsham going south --correct me if I'm wrong.

[astockfan101]

Class 501's were also fourth rail at one time when they were built in the late 1950's.

[norbitonflyer]

Indeed - converted in 1970, allowing a Southern 4COR to make a tour to Broad Street and Croxley Green!

[bassmike]

The 501's wern't totally without problems when converted to 3rd rail-- owing to lack of earthing brushes on the axles,they were stopped with pitted roller bearings caused by the bearings having to pass the return current and they were hurriedly reverted to 4 rail until the remedy was fitted.
Units such as Sarah Siddons had plain bearings and did not suffer this problem when running on 3rd rail with the neg: shoe leads bolted to the motor casings,(although it probably didnt improve them very much)

[bassmike]

Incidentally Sarah Siddons ran quite happily on 700/750 volts when visiting Dover Marine and Portsmouth on railtours. Electric motors of this type are not too fussy (within reason) abouit voltage as if the voltsre higher then the back-EMF rises and limits the current. The main problem with higher voltages is light-bulbs etc:

[Deleted]

Generally traction motors on LU are tested upto 1000v DC

[Dstock7080]

Some information today:

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.

[John Tuthill]

Oct 19, 2016 8:58:11 GMT Dstock7080 said:

Some information today:

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.

And call it a 'Metadyne?'

[stapler]

How do they get to a third capacity increase? Surely the signalling upgrade wd be responsible for most of that?
Could the same be applied to the tube lines?

[patrickb]

Has the voltage increase to 750v been already implemented? If so, how has this been achieved whilst the A Stock is still on Leaf-Fall Duties?

[phil]

Oct 19, 2016 20:01:03 GMT patrickb said:

Has the voltage increase to 750v been already implemented? If so, how has this been achieved whilst the A Stock is still on Leaf-Fall Duties?

Given the A stock being retained for such duties is tiny in number, I wouldn't have thought it hard for LU to have made the necessary modifications to them over the summer while they were not required.

[Deleted]

All trains including A stock and engineering trains are rated upto 1000v DC

[philthetube]

Oct 19, 2016 8:58:11 GMT Dstock7080 said:

Some information today:

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.

what tunnel lighting?  I don't think the north curve has any.

[Deleted]

Apr 5, 2015 10:42:04 GMT @notatraindriver said:

Mar 19, 2015 0:56:18 GMT North End said:

The Northern Line has recently developed the superb spectacle in the Stockwell area that at peak times on certain days, move the handle to full motors and the tunnel lights come on, shut off and they go off!

On the subject of the Wimbledon branch, the restrictions are a little strange, as the SA shows classes 450 and 458 as restricted, but not class 444.

As far as I'm aware class 444s are already restricted in power which is why they may not be restricted the way 450s and 458s are.

I'd always thought it was because the maximum length 444 formation (10 cars) only had 4 motor coaches whereas the maximum length 450 (12 cars) and 458 (8 cars) had 6 motor coaches (450s 2 per set, 458s 3 per set)