IoW light rail conversion proposed

[KeithHC]

I seam to recall reading about the mixing of 3rd rail units and 4th rail units on part of the sw suburban network. It has something to do with changing the polarity of the 4th rail. There is a change over point I think somewhere around Putney.

 

Keith

[phil-b259]

9 minutes ago, KeithHC said:

I seam to recall reading about the mixing of 3rd rail units and 4th rail units on part of the sw suburban network. It has something to do with changing the polarity of the 4th rail. There is a change over point I think somewhere around Putney.

 

Keith

 

Where Underground and National rail share a conductor rail power supply, the centre rail is bonded to both running rails - LU trains do NOT* have the ability to return traction current to the running rails like Nation Rail trains do.

 

This arrangement gives both trains the 600 - 700V voltage difference necessary to power them. On LU proper the voltage difference remains the same - only its split into +400(ish)V (3rd rail) and -200(ish)V (4th rail). On National Rail the voltage is split between 600 - 700V on the 3rd rail and 0V on the running rails

 

*Sarah Siddons had some pretty significant modifications in the 1980s to allow use on pure 3rd rail systems

 

On the Wimbledon branch the changeover is done on Putney Bridge with a dead section slightly longer than a District line change so as to avoid linking the two systems as trains pass from one to the other. Similarly the Richmond branch has a dead section between Gunnesbury and Turnham Green.

[phil-b259]

1 hour ago, John M Upton said:

I doubt Sarah Siddons would fit through Ryde Tunnel but the possibility is intriguing. 

 

Does the Island Line have mainland safety systems, e.g. AWS and TPWS? 

 

IIRC it had tripcocks as befitting ex tube stock (possibility also related to the ability to fit TPWS gear / receivers onto the trains).

 

However given the replacement ex District line trains are bigger and have successfully had TPWS fitted for mainland use then I imagine TPWS will be fitted instead

[KeithHC]

What about Southern loaning a couple of 313’s. I am sure John Upton would volunteer to teach the SWR guys to drive them.

 

Keith

[Mike Storey]

This problem must be serious - there must be indications of wrong-side failures in running, which points to compatibility with the signalling system. I cannot think of anything else which would require a wholesale review of the software introduced. It cannot just be a frequency issue, or eddy currents. A traction issue on the 3rd rail would just require some minor tweaking, to ensure effectiveness on the third rail, either by the supply or by the on-board systems. Any other views?

 

Either way, this is bad news, both for the IOW, and for VivaRail.

[Foulounoux]

Vivarails honesty on various social media platforms in taking responsibility for the issue is to be applauded

Their social media person was very busy yesterday on Twitter not only on their own stream but also deflecting criticism from  those blaming SWR 

 

Edited April 28, 2021 by Foulounoux
Make clearer nature of swr responses

[Mike Storey]

13 minutes ago, Foulounoux said:

Vivarails honesty on various social media platforms in taking responsibility for the issue is to be applauded

Their social media person was very busy yesterday on Twitter not only on their own stream but also deflecting criticism from  those blaming SWR 

 

 

Oh, ok. Fair enough then. But I am not sure they had any alternative???

[mdvle]

1 hour ago, Mike Storey said:

 

Oh, ok. Fair enough then. But I am not sure they had any alternative???

 

They could have remained silent, they could have stood by while people blamed SWR.

 

Yes, they are responsible for the delay but they could have handled it differently / worse.

[roythebus1]

Sarah Siddons runs on third rail because it doesn't have fancy computer systems on board apart from the TWPS and AWS stuff. It's only since the widespread introduction of computers on trains that these sort of reliability problems have arisen. Computers are for teenagers with nothing better to do.

I don't see why SS shouldn't fit through Ryde Tunnel, but with very little rolling stock to pull apart from a few pw wagons, it wouldn't be much use. Unless of course the IWSR would alone SWR some vintage stock. but then there's no run-rounds anywhere.

[PhilJ W]

Sarah Siddons is a big locomotive, power equivalent of a 37 IIRC. She certainly would not fit into the tunnels at Ryde. 

[009 micro modeller]

5 minutes ago, roythebus1 said:

Unless of course the IWSR would alone SWR some vintage stock. but then there's no run-rounds anywhere.

 

Is the LU 4TC capable of push-pull working with Sarah Siddons, or anything else it’s commonly used with?

[roythebus1]

It is capable of push-pull with 33/1 and 73/1 and any compatible BR/SR EMU stock. It can be pushed by SS but needs a driver at the front to use the brake and a driver on the loco to make it go with radio communication between the two. BR C1 stock won't fit the IWR.

[PhilJ W]

4 minutes ago, 009 micro modeller said:

 

Is the LU 4TC capable of push-pull working with Sarah Siddons, or anything else it’s commonly used with?

Yes.

[Joseph_Pestell]

5 hours ago, PhilJ W said:

Sarah Siddons is a big locomotive, power equivalent of a 37 IIRC. She certainly would not fit into the tunnels at Ryde. 

 

I don't see that the power of an electric locomotive has anything to do with size when compared with a not very powerful diesel.

 

Better to look at where Sarah Siddons could go, the somewhat restricted tunnels north of Baker St, which the D78 stock were not, I think, cleared for. So, it would seem, anywhere a D78 can go, Sarah Siddons should be OK.

[Zomboid]

Would the pier be able to support a locomotive?

 

Putting aside the fact that to run the train service they'd need two.

[rodent279]

7 hours ago, PhilJ W said:

Yes.

Really? Sarah can run in multi with a TC?

[PhilJ W]

3 hours ago, Joseph_Pestell said:

 

I don't see that the power of an electric locomotive has anything to do with size when compared with a not very powerful diesel.

 

Better to look at where Sarah Siddons could go, the somewhat restricted tunnels north of Baker St, which the D78 stock were not, I think, cleared for. So, it would seem, anywhere a D78 can go, Sarah Siddons should be OK.

The D78's were restricted due to their length (outswing).

1 hour ago, rodent279 said:

Really? Sarah can run in multi with a TC?

Has done so for years with London Transports own TC set which was the one used on the main line.

[rodent279]

Well there you go, I've learnt something new there. Thanks!

[Nick C]

Regarding how these trains worked on the District - remember that they didn't - they are in effect new trains that just happen to use the old shells and underframes of the District stock. All the motors, control gear etc is new, and that seemingly is what's causing the problems.

[Mike Storey]

13 hours ago, mdvle said:

 

They could have remained silent, they could have stood by while people blamed SWR.

 

Yes, they are responsible for the delay but they could have handled it differently / worse.

 

Yes, they could. But I suspect this is as much to do with trying not to get sued (or a big compensation claim - good luck with that), and trying to keep their reputation intact for other sales. 

[stewartingram]

10 hours ago, PhilJ W said:

The D78's were restricted due to their length (outswing).

Has done so for years with London Transports own TC set which was the one used on the main line.

When used on the Met with the 4TC, SS was at one end and a loco at the other for the return journey. And often there would be an extra loco at one end, or both, so the 4TC was in reality just loco-hauled stock, not used in 'push' mode.

[009 micro modeller]

6 hours ago, stewartingram said:

When used on the Met with the 4TC, SS was at one end and a loco at the other for the return journey. And often there would be an extra loco at one end, or both, so the 4TC was in reality just loco-hauled stock, not used in 'push' mode.

 

In that case, was there a reason why LU chose to purchase a 4TC, rather than more conventional hauled stock?

[Christopher125]

Remember these have a new traction package with AC motors, and these tend to struggle with the 3rd rail I think it's safe to say?

 

Getting them to behave has often required extensive testing at Old Dalby, Wildenrath, Bournemouth etc but Vivarail ran out of time on the island and some limited running on Bombardier's short test track never seemed sufficient.

 

 

Edited April 30, 2021 by Christopher125

[Not Jeremy]

20 hours ago, Mike Storey said:

 

Yes, they could. But I suspect this is as much to do with trying not to get sued (or a big compensation claim - good luck with that), and trying to keep their reputation intact for other sales. 

 

Call me stupid, but I prefer to think that he is a decent bloke running a decent company with a highly innovative product that has a few issues that need sorting out.

 

Personally I would dearly love to see  such an approach or attitude from absolutely anyone involved in setting up the circumstance that gave us the horror of Grenfell Tower, or the utterly disgusting and wrong headed Post Office "Horizon" prosecutions. I have no doubt whatever that we will see no such thing, no matter how many enquiries are set up.

 

So, to return to Vivarail, I think the current developments on the island are brilliant, especially after all the daft suggestions and doom laden hand wringing we saw at the beginning of this thread.

 

Thank you to all the contributors who have provided such fascinating pictures and insights into what is going on.

 

Simon

[bude_branch]

On 20/04/2021 at 23:53, Christopher125 said:

All the new signals at Brading are now up, though only one has route indicators curiously.

Brading by Chris, on Flickr

 

I would still like to know why that signal has two sets of Lunar Lights?  To me it seems contrary to standard signalling practice for two routes; i.e. main aspect for the principal route, main aspect and lunar lights for the diverging route.  Perhaps things have moved on since my day