GWML Electification

[Joseph_Pestell]

16 minutes ago, The Stationmaster said:

Maybe a better idea would be to close the bridge and keep the level crossings?      The present performance is an utter nonsense and one day somebody is going to forget what they are supposed to do (notwithstanding the auto arrangement for some trains)  and the results might be interesting if not necessarily spectacular or dangerous.  It really is utterly ludicrous in this day and age that a major rail route which is newly, and eventually, being electrified should have to be worked in what amounts to a totally ridiculous manner all because Brunel signed a drawing and some idiot thinks that means he built the bridge with his own hands to his own design.  

 

Presumably, we are talking about the bridge at the east of Steventon (the old A34).

 

Notwithstanding any original Brunel input, that bridge has been rebuilt/modified so much over the years that it certainly does not merit a listed status.

[jamie92208]

I think that whatever solution is eventually chose, someone is going to be upset.   I wonder if there is money to be made by opening a book on whether the masts at Goring get rebuilt before Steventon is sorted.

 

Jamie

[The Stationmaster]

5 minutes ago, jamie92208 said:

I think that whatever solution is eventually chose, someone is going to be upset.   I wonder if there is money to be made by opening a book on whether the masts at Goring get rebuilt before Steventon is sorted.

 

Jamie

I think we could get a number of things in there -

1.  Revised masts at Goring - about 5,000:1 and in any case not before CP 20 something

2. Steventon bridge dealt with properly - probably about 1,000:1 within the next 5 Control Periods unless there is an 'incident' because that will drastically shorten the odds.

3. Electrification to Bristol TM via either route - about 1,000:1 within the next 10 Control Periods.

4. Electrification of the Thames Valley branches (currently standing 'deferred') - at least several million to one.

5.  Electrification beyond Cardiff to Swansea. - about 10.000:1 within the next 5 Control Periods

6. Major works on the sea wall in South Devon - about 500:1 within the next two Control Periods.

7. Crossrail opening completely before the end of 2020 - about 2:1. (actually I confidently predict that it will open, in full, no later than April 2020.  N.B.The next London Mayoral election is in May 2020)

 

Of course if Chris Grayling were to spend more time with his family some of the above odds might well change, except the one in respect of masts in the Goring area.

[Joseph_Pestell]

17 minutes ago, jamie92208 said:

I think that whatever solution is eventually chose, someone is going to be upset.   I wonder if there is money to be made by opening a book on whether the masts at Goring get rebuilt before Steventon is sorted.

 

Jamie

 

I can't see much reason for the folk in Steventon south of the railway to be upset if a new road is built to get them to High Street (old A34). Has to be better than endless queuing at those two level crossings. There would need to be at least one footbridge built so that the children can get to primary school.

[rodent279]

1 hour ago, The Stationmaster said:

Maybe a better idea would be to close the bridge and keep the level crossings?      The present performance is an utter nonsense and one day somebody is going to forget what they are supposed to do (notwithstanding the auto arrangement for some trains)  and the results might be interesting if not necessarily spectacular or dangerous.  It really is utterly ludicrous in this day and age that a major rail route which is newly, and eventually, being electrified should have to be worked in what amounts to a totally ridiculous manner all because Brunel signed a drawing and some idiot thinks that means he built the bridge with his own hands to his own design.  

I suspect the bridge has been rebuilt at some point anyway. Surely it would have been when the route was quadrupled?

[rodent279]

Apologies if this has already been shared.

 

https://www.railengineer.uk/2018/08/30/steventon-bridge-demolition-local-voice-rejects-proposed-10-months-of-disturbance/

[Joseph_Pestell]

22 minutes ago, rodent279 said:

Apologies if this has already been shared.

 

https://www.railengineer.uk/2018/08/30/steventon-bridge-demolition-local-voice-rejects-proposed-10-months-of-disturbance/

 

Thanks for that link. A very interesting piece and well-written.

 

The Parish Council seem like a difficult lot! Of course, there is reasonable concern for the businesses on the High St but surely it's possible to provide some temporary solution that keeps the traffic flowing during the reconstruction.

 

It reminds me of a situation that occurred near Bath when an A-road had to be closed for works, involving a 20-mile diversion for road users. An enterprising farmer put in a temporary roadway through his adjoining field and charged a toll. There is plenty of open ground around Steventon to take the same approach, minus the toll of course, with a temporary bridge across the railway (about 100m east of the current bridge).

Edited February 7, 2019 by Joseph_Pestell
Added info

[Joseph_Pestell]

1 hour ago, rodent279 said:

I suspect the bridge has been rebuilt at some point anyway. Surely it would have been when the route was quadrupled?

 

Only two tracks through the bridge. The four tracks start just east of there.

 

But yes. That bridge is an old broom with new head and handles over the years.

[rodent279]

36 minutes ago, Joseph_Pestell said:

 

Thanks for that link. A very interesting piece and well-written.

 

The Parish Council seem like a difficult lot! Of course, there is reasonable concern for the businesses on the High St but surely it's possible to provide some temporary solution that keeps the traffic flowing during the reconstruction.

 

It reminds me of a situation that occurred near Bath when an A-road had to be closed for works, involving a 20-mile diversion for road users. An enterprising farmer put in a temporary roadway through his adjoining field and charged a toll. There is plenty of open ground around Steventon to take the same approach, minus the toll of course, with a temporary bridge across the railway (about 100m east of the current bridge).

Yes, that was the A431 near Kelston. After a lot of heavy rain, the hillside ground supporting the road became unstable, so it was closed. The work took about a year from memory, I think it was the same time that Dawlish got washed away.

It's usually quite a busy road, but for us Bitton road runners, it was great-we had the road to ourselves! Bitton station to Bath via Kelston and back via the Bristol-Bath cycle path became a popular Sunday morning run!

Google maps still shows the diversion running through the field!

Edited February 7, 2019 by rodent279

[caradoc]

5 hours ago, The Stationmaster said:

I think we could get a number of things in there -

1.  Revised masts at Goring - about 5,000:1 and in any case not before CP 20 something

2. Steventon bridge dealt with properly - probably about 1,000:1 within the next 5 Control Periods unless there is an 'incident' because that will drastically shorten the odds.

3. Electrification to Bristol TM via either route - about 1,000:1 within the next 10 Control Periods.

4. Electrification of the Thames Valley branches (currently standing 'deferred') - at least several million to one.

5.  Electrification beyond Cardiff to Swansea. - about 10.000:1 within the next 5 Control Periods

6. Major works on the sea wall in South Devon - about 500:1 within the next two Control Periods.

7. Crossrail opening completely before the end of 2020 - about 2:1. (actually I confidently predict that it will open, in full, no later than April 2020.  N.B.The next London Mayoral election is in May 2020)

 

Of course if Chris Grayling were to spend more time with his family some of the above odds might well change, except the one in respect of masts in the Goring area.

 

Stationmaster, you've missed out the most important bit; Wiring Didcot to Oxford ! (Unless that counts as a Thames Valley Branch ?!)

 

Anyway, I believe I have a solution to Steventon; Build a Gerrards Cross-style covered way over the railway to provide a new road bridge, eliminate the LCs, and give space for a lovely big supermarket in the heart of the village. Everyone's a winner !

 

[The Stationmaster]

4 hours ago, Joseph_Pestell said:

 

Only two tracks through the bridge. The four tracks start just east of there.

 

But yes. That bridge is an old broom with new head and handles over the years.

From what I delved out in the past I think the side arches were part of the original construction as it had to span quite a distance.  But it is very definitely an old broom with numerous new parts - both of the side arches have been strengthened with horizontal site cast concrete beams obviously intended to help relieve the loading of the piers for the main arch;  the north (village) end appears to have been more or less completely rebuilt on the west face with what is very obviously modern brickwork which no longer matches the south end on that side (and probably doesn't match the original drawing either?); the faces of two arches have also been rebuilt in modern brickwork which is hardly surprising as even a pre 1914 photo shows some of the brickwork to have been in poor condition and in need of renewal.  And the bridge has had visible tie bars to stop the brickwork playing outwards above arch level for many years.

 

None of this comes as any surprise on  bridge which for years carried increasingly heavy traffic on the A34 until that was rebuilt to bypass the village.  And also of course a bridge under which trains have been passing at speed, which increased to 125 mph in the 40 years of the  HST era, and on a l route used by maximum axleweight freight traffic.

[rodent279]

Maybe the solution is to move the old bridge to a new site, Pegasus Bridge style? Wouldn't solve the need to close the railway or the road though.

[St. Simon]

36 minutes ago, rodent279 said:

Maybe the solution is to move the old bridge to a new site, Pegasus Bridge style? Wouldn't solve the need to close the railway or the road though.

 

Hi,

 

Amazingly, I did have someone (outside of the railway industry I may add) try to convince me that the solution to allowing linespeed through Steventon and pleasing the locals was building a new 125mph ready bridge next to the old bridge and leave the old bridge in place.....

 

I'm still trying to work out the logic behind that one.

 

Simon

[corneliuslundie]

I don't really think that for the locals the listing is relevant. They just don't want the disruption of having a replacement bridge built, or any significant change in any other way, and the listing is being used as a - pretty well irrelevant - reason for blocking the rebuilding because it allows the district council to prevent the work.

I must admit that I would not be enthusiastic either. But there are far worse things happening in the wider area which they either seem blind to or know they cannot conrol.

Jonathan

[Joseph_Pestell]

If the catenary wire was replaced with "rail" (as in the Severn Tunnel), would that allow a more severe change in gradient of the OHE between the level crossing and the bridge and/or reduced clearance below the bridge?

 

Might not enable full line speed but better than 60mph???

[jamie92208]

2 hours ago, Joseph_Pestell said:

If the catenary wire was replaced with "rail" (as in the Severn Tunnel), would that allow a more severe change in gradient of the OHE between the level crossing and the bridge and/or reduced clearance below the bridge?

 

Might not enable full line speed but better than 60mph???

 

2 hours ago, Joseph_Pestell said:

 

I'm no expert on this but I think the problem is the gradient of the catenary between lowest possible under the bridge and highest over the level crossing.  That imposes a lot of forces on a pantograph moving at 125 and both that and the OHLE equipment wear at a high rate.   It may well be that the rapid change of height is outside the designed operating parameters for the pantograph.

 

Jamie

 

[Edwin_m]

Yes, the force on the pantograph depends on the gradient of the wire relative to the track and on the speed of the train.  When the wire is descending the force increases and may increase wear, and when it is ascending the pantograph may not be able to keep up resulting in arcing and more wear.  So options like lowering the whole line including the level crossings don't work, as the key parameter is the difference in height between the bridge and the clearance needed for the wire over the crossings.  Running electric trains more slowly reduces the rate at which the pantograph has to raise or lower to follow the wire. 

[rodent279]

All the above, in regard to Steventon bridge, serves to illustrate what an integrated system a railway is. Almost every component part has a bearing in some way or other on some or all of the rest of the system, you just can't view it as a series of isolated, independent systems.

 

It also serves to illustrate the difference between upgrading a railway for high speed, and building a new one specifically for high speed, in which the trains and infrastructure are designed as a whole.

[St. Simon]

5 hours ago, Joseph_Pestell said:

If the catenary wire was replaced with "rail" (as in the Severn Tunnel), would that allow a more severe change in gradient of the OHE between the level crossing and the bridge and/or reduced clearance below the bridge?

 

Might not enable full line speed but better than 60mph???

 

Hi,

 

Technically the OLE through Stevenson is fit for 125mph, but only occasionally (once or twice in total), it is the wear rate on the contact wire and forces on Pantograph due to the wire gradient  that forces the 60mph limit.

 

The Bridge needs to be replaced (or the level crossing closed) before 125mph on electric can be regularly done through that  area. I'm afraid to say that it is the only solution

 

simom

Edited February 8, 2019 by St. Simon

[jim.snowdon]

If the pantographs can be got under the bridge, as they can, the better solution is to remove the level crossings simply because that removes a whole series of other safety risks associated with them, and fulfills another element of Network Rail policy. Technically, it is doable, but would require some land purchase to create the necessary new road along the south side of the railway. The residents probably wouldn't like it either, as it would make getting between the north and south sides of the village something of a detour.

 

At the moment though, there is always the option of coasting through with the pantograph(s) down, assuming that there are no awkwardly placed wire overlaps or sectioning insulators. Sometimes solutions needs a bit of lateral / interdisciplinary thinking.

 

Jim

[Coryton]

1 hour ago, jim.snowdon said:

If the pantographs can be got under the bridge, as they can, the better solution is to remove the level crossings simply because that removes a whole series of other safety risks associated with them, and fulfills another element of Network Rail policy. Technically, it is doable, but would require some land purchase to create the necessary new road along the south side of the railway. The residents probably wouldn't like it either, as it would make getting between the north and south sides of the village something of a detour.

 

At the moment though, there is always the option of coasting through with the pantograph(s) down, assuming that there are no awkwardly placed wire overlaps or sectioning insulators. Sometimes solutions needs a bit of lateral / interdisciplinary thinking.

 

Jim

I thought the plan was effectively that, but using the diesels rather than coasting.

[Zomboid]

That's what they're doing now. Seems to me that it'll just cause unnecessary wear to the diesel engines, which can't keep up when trains are doing linespeed anyway.

 

Not being dogmatic about it, it's actually not a terrible solution (so long as coasting is used rather than diesel). Stopping or low speed trains don't suffer an interruption in their line light, and fast trains can still pass at high speed. They might be putting the pan back up at 110 rather than 125, but that shouldn't have a major detrimental effect on journey times when the improved acceleration of an electric train is accounted for (from rest at all stops rather than the 110-125 bit).

[rodent279]

50 minutes ago, Zomboid said:

That's what they're doing now. Seems to me that it'll just cause unnecessary wear to the diesel engines, which can't keep up when trains are doing linespeed anyway.

 

Not being dogmatic about it, it's actually not a terrible solution (so long as coasting is used rather than diesel). Stopping or low speed trains don't suffer an interruption in their line light, and fast trains can still pass at high speed. They might be putting the pan back up at 110 rather than 125, but that shouldn't have a major detrimental effect on journey times when the improved acceleration of an electric train is accounted for (from rest at all stops rather than the 110-125 bit).

It still seems backwards and bizarre, when as mentioned further back, we can destroy whole swathes of urban London for a runway, but we can't rebuild a bridge serving a small village in the sticks.

[jamie92208]

In the long term I thought that the plan was to take most of the extra diesel engines off the 800's as more routes are wired.  That would make the diesel option more tricky especially trying to make sure that all trains that stopped at Didcot were still diesel fitted.   Longer

this situation has to be sorted.

 

Jamie

[Zomboid]

20 minutes ago, rodent279 said:

It still seems backwards and bizarre, when as mentioned further back, we can destroy whole swathes of urban London for a runway, but we can't rebuild a bridge serving a small village in the sticks.

Absolutely, it's ridiculous. But if it really is that difficult, then making the best of a bad job in this instance isn't actually a catastrophe.