GWML Electification

[jim.snowdon]

12 hours ago, phil-b259 said:

Thing is that if the OLE is only for depot purposes it doesn't have to be particularly big and as such will not necessarily require connection to the 33KV super-grid original required for the proper electrification scheme.

True for the low power requirements required for depot testing, but for the main lines, the electrical supplies are taken from as high up the grid network as practicable, preferably 400kV. The problem is the extent to which single phase AC traction puts an unbalanced load on the three phase grid supply. 

The super grid is that part of the electrical supply network operating at 264 or 400kV. From 132kV downwards is now the province of the Regional Electricity Companies.

 

Jim

[Zomboid]

A little depot connection can come from a low voltage - there is one at Blackpool from 33kV, which cannot supply the main lines but can keep the sidings live if there's an isolation between there and Preston. A couple of depots on the southern where dual voltage stock is kept have similar facilities from the 33kV for testing and maintenance purposes.

 

But at Swansea it's probably not worth it, since no train that can't move without electricity can arrive there anyway.

[Edwin_m]

10 minutes ago, Zomboid said:

A little depot connection can come from a low voltage - there is one at Blackpool from 33kV, which cannot supply the main lines but can keep the sidings live if there's an isolation between there and Preston. A couple of depots on the southern where dual voltage stock is kept have similar facilities from the 33kV for testing and maintenance purposes.

 

But at Swansea it's probably not worth it, since no train that can't move without electricity can arrive there anyway.

It does mean that a train arriving with an OLE-related fault probably can't have it repaired until it can be worked to another depot, as the repair is likely to need a test on 25kV.  If there really is no 25kV at Maliphant them maybe this explains the number of 80x that are reported running on diesel on sections where the OLE is energised and cleared for use. 

[Zomboid]

That's true, the high voltage electrical systems can't be tested in Swansea (or indeed Plymouth).

 

Guess it's one of the unintended consequences of cursing the GW with bi-modes.

[Richard_A]

I drive past maliphant depot most days and I've never noticed any overhead wires, just steel structures.

[The Stationmaster]

On 25/04/2019 at 14:16, rka said:

I drive past maliphant depot most days and I've never noticed any overhead wires, just steel structures.

Maliphant was definitely wired but I have heard that the wires have been removed - which strikes me as rather daft if that is the case as it can no longer do any sort high voltage tests.

[Richard_A]

56 minutes ago, The Stationmaster said:

Maliphant was definitely wired but I have heard that the wires have been removed - which strikes me as rather daft if that is the case as it can no longer do any sort high voltage tests.

Sounds so ridiculous that it must be true.

[Northroader]

We haven’t been told who removed them, perhaps the Swansea copper fairies just magicked them away.

[Zomboid]

5 hours ago, The Stationmaster said:

Maliphant was definitely wired but I have heard that the wires have been removed - which strikes me as rather daft if that is the case as it can no longer do any sort high voltage tests.

It never could. The nearest feeder station is at Thingley Junction. Or possibly one of the ones in Birmingham, not really sure of the distances around there. So there would have been no way to get any high voltages onto the wires.

[roundhouse]

Today we were on a 802 to Cardiff, diesel from Didcot onwards. While the seats are more comfy than a  Thameslink GWWorm my back was sore when we got off at Cardiff and I was limping for a while till the medication kicked in at the Wig and Pen. OK till back on one to Reading but having to walk four coaches to find a working toilet isn't good although the trolley bloke did sort out the ones in our coach as I got back to our coach. Glad to be on a 166 as the seats are way better.

[Edwin_m]

2 hours ago, Zomboid said:

It never could. The nearest feeder station is at Thingley Junction. Or possibly one of the ones in Birmingham, not really sure of the distances around there. So there would have been no way to get any high voltages onto the wires.

I think getting a 25kV supply just to power up the train for testing could be done without a fully-fledged feeder station - I believe for example they were intending to install something in the Supertram depot for the tram-trains until someone decided it wasn't worth it as they would only run on 750V.  On the other hand if someone tried to move the train on electric power then I imagine hte breaker would drop out pretty quicly. 

[phil-b259]

2 hours ago, Zomboid said:

It never could. The nearest feeder station is at Thingley Junction. Or possibly one of the ones in Birmingham, not really sure of the distances around there. So there would have been no way to get any high voltages onto the wires.

 

You do NOT need a very high power feeder station to provide a depot only 25KV testing facility!  The current supply grid in Swansea is perfectly capable if supplying the limited amount of power a depot only facility would require.

 

If the powers that be had any sense then a short bit of 25KV would be installed at Maliphant and Liara to allow the electrical propulsion systems to be checked / repaired rather than have to let the units run round on diesel till they next visit Soke Gifford or North pole.

Edited May 5, 2019 by phil-b259

[david.hill64]

6 hours ago, phil-b259 said:

 

If the powers that be had any sense 

 

Come on Phil, you've been in the industry to know that such wishful thinking is just wishful thinking..............

[Zomboid]

7 hours ago, phil-b259 said:

 

You do NOT need a very high power feeder station to provide a depot only 25KV testing facility!  The current supply grid in Swansea is perfectly capable if supplying the limited amount of power a depot only facility would require.

 

If the powers that be had any sense then a short bit of 25KV would be installed at Maliphant and Liara to allow the electrical propulsion systems to be checked / repaired rather than have to let the units run round on diesel till they next visit Soke Gifford or North pole.

That's true, and there are a couple of examples of low powered 25kV supplies knocking around for depot purposes (Blackpool and Selhurst come to mind). But there isn't any kind of 25kV supply in Swansea and never has been, so any wires which may have been installed there have never been live.

[jim.snowdon]

10 hours ago, Zomboid said:

It never could. The nearest feeder station is at Thingley Junction. Or possibly one of the ones in Birmingham, not really sure of the distances around there. So there would have been no way to get any high voltages onto the wires.

I find it very hard to believe that the line all the way to Cardiff would be fed from the English side to start with.

 

 In any case, just how much 25kV equipment is there on an 8xx unit that needs testing to start with? Not much, I suspect, beyond a pantograph, the HV transformers and the HV bus line. From the secondary side of the transformer onwards, it will all be LV equipment capable of being powered from a shore supply.

 

Jim

[Titan]

On 25/04/2019 at 09:35, jim.snowdon said:

The problem is the extent to which single phase AC traction puts an unbalanced load on the three phase grid supply. 

 

Jim

 

This is not a problem any more. Inverter feeder stations can be used which take in three phase, and change it to single phase AC. This means that a single phase AC supply can load all three phases of the incoming supply equally.

[jim.snowdon]

1 hour ago, Titan said:

 

This is not a problem any more. Inverter feeder stations can be used which take in three phase, and change it to single phase AC. This means that a single phase AC supply can load all three phases of the incoming supply equally.

Yes, although so far, I believe that there is only one on the UK railway system, associated with the Hitachi depot at Doncaster. The technology is not novel, HV DC:3-phase AC having been around for some time now.

 

Jim

[DY444]

On 24/04/2019 at 20:24, phil-b259 said:

 

Are you sure about that?

 

The HS1 Hitachi depot at Ashford and the Siemens Thameslink depot at Three Bridges* (and the Southern depot at Selhurst IIRC) all have short bits of 25KV OLE to test the dual voltage EMUs after servicing. The last thing GWR want is a 800 to become a total failure on the GWML when under electric power east of Cardiff.

 

If the Swansea facility undertakes maintenance activities (rather than simple stabling - which includes exterior + interior cleaning, washing / emptying toilet retention tanks etc) then I would expect it to have some form of OLE - and it would be sensible to do this via the bits already installed under the aborted SWML electrification plan

 

 

100% sure.

 

I can't comment on Three Bridges because I'm not familiar with the Siemens maintenance philosophy but Selhurst and Ashford are operated very differently to each other.  Hitachi will not carry out AC maintenance of any kind at a depot that does not have ole that is capable of being energised to check the train after the work.  This is why there were so many IETs running on diesel under the wires before Stoke Gifford was energised.  If a unit requiring AC system maintenance or repair arrived at Stoke Gifford then the work was deferred until it could be worked to North Pole and in the meantime the unit was released to traffic with a diesel only restriction.  So to that extent the non-wiring of Maliphant means that replacement of pan carbons cannot be done there, otherwise it makes no material difference as anything more serious would have had to be done at Stoke Gifford or North Pole anyway.  I don't believe that Hitachi have any requirement for an AC systems test on every train before entering service because this would not be possible at non-electrified outposts where units were stabled.

 

Selhurst is different.  The test facility there is only used after major repairs to AC systems not after routine maintenance like changing of pan carbons.  Again Southern AC units are not tested daily despite them having diagrams which take them onto the WLL and WCML.  

 

Thameslink is a case of learning lessons the hard way and the potential consequences.  If you look back at the train failure stats pre class 700, the biggest cause by a country mile is traction changeover issues in the core.  If an IET won't take AC power then it can carry on using diesel and will cause a few delays.  If a 377/2 won't changeover at White City then it's going to cause quite a bit of local inconvenience on the NLL and WLL.  If a 700 won't changeover at City or Farringdon then it could totally trash the BML, the MML and the ECML which would be a catastrophe.

 

Edited May 6, 2019 by DY444

[Zomboid]

11 hours ago, jim.snowdon said:

I find it very hard to believe that the line all the way to Cardiff would be fed from the English side to start with.

There will be a feeder station in Wales, it's just not there yet, or able to supply any power to Swansea.

[The Stationmaster]

On 06/05/2019 at 05:05, david.hill64 said:

 

Come on Phil, you've been in the industry to know that such wishful thinking is just wishful thinking..............

Ah, but Hitachi haven't been involved for that long and as there might be money at stake it does eem a little odd that they didn't take a more radical (by UK standards) approach to things.

[Edwin_m]

18 hours ago, Zomboid said:

There will be a feeder station in Wales, it's just not there yet, or able to supply any power to Swansea.

I belive there's one just east of Cardiff, and as this section isn't fully wired yet it can't be supplying any power although it may be commissioned.  It won't be supplying power to Swansea in the foreseeable...

[Jonboy]

Steventon bridge.....again......https://www.oxfordmail.co.uk/news/17671357.steventon-rail-bridge-demolition-will-go-to-public-hearing/?fbclid=IwAR0NIDQQCXyAEIbtKbHrVZqwfFKW-YL5KkjSeKGgJxxi_NJEklarZL3FXX0

[royaloak]

18 minutes ago, Jonboy said:

Steventon bridge.....again......https://www.oxfordmail.co.uk/news/17671357.steventon-rail-bridge-demolition-will-go-to-public-hearing/?fbclid=IwAR0NIDQQCXyAEIbtKbHrVZqwfFKW-YL5KkjSeKGgJxxi_NJEklarZL3FXX0

Closure of the crossings would be the other option.

[Mike Storey]

46 minutes ago, Jonboy said:

Steventon bridge.....again......https://www.oxfordmail.co.uk/news/17671357.steventon-rail-bridge-demolition-will-go-to-public-hearing/?fbclid=IwAR0NIDQQCXyAEIbtKbHrVZqwfFKW-YL5KkjSeKGgJxxi_NJEklarZL3FXX0

 

On 23/04/2019 at 14:06, DY444 said:

Reports circulating that the line speed for electric traction under the infamous Steventon bridge is to be raised to 115mph in September.

 

It is hard to work out what is going on. Is the latter report true? If it is, what is the point of the Appeal?

 

[Jonboy]

I dunno about the line speed but the road speed could do with be dropped to 15mph due to the dips that are appearing in the road surface.