Great Western Electrification Progress

[LNW-GW Joint]

I would imagine the larger loading gauge gives more room for equipment and probably reduces costs. I'm not aware the French have been doing much in the way of electrification of existing routes, though they have been building new railways.

They have been continuously electrifying existing routes, often in conjunction with new TGV lines or extensions, so that TGVs can run through.
Most of Brittany for instance, and Alsace.

 

[jyte]

Crossrail tweeted a video clip of the Acton Diveunder.

https://twitter.com/Crossrail/status/816334939767640064

Yes! I was just thinking it looked like the Acton Diveunder had opened.

 

[Hophead]

They have been continuously electrifying existing routes, often in conjunction with new TGV lines or extensions, so that TGVs can run through.
Most of Brittany for instance, and Alsace.

In a larger, less densely populated country, there are likely to be fewer road over rail bridges to contend with; particularly so now that we know the initial section out of Paris is already wired.

 

[NotATrainspott]

Bi-modes don't work with proper high speed train designs either. Before wiring up the extremities of the network, the TGVs had to be dragged by diesel locomotives. The only bi-mode high speed trains that I'm aware of are the high speed RENFE Class 730 units which have an additional diesel power trailer joined to the standard electric power car at either end. Even then it's still a 250km/h design rather than the standard 320km/h.

 

[LNW-GW Joint]

The only bi-mode high speed trains that I'm aware of are the high speed RENFE Class 730 units which have an additional diesel power trailer joined to the standard electric power car at either end. Even then it's still a 250km/h design rather than the standard 320km/h.

There are other (electric) 250km/h designs in Spain - the ones which change gauge, of which there are a surprising number.
In fact the Renfe bi-modes seem to be down to one route and 3 services each way to Galicia, and they will soon be redundant because the AVE line is nearly ready.

 

[SWT_USER]

Passed through the diveunder this morning on a HC service. How much time is lost using the diveunder vs not using it? Not a huge amount obviously but it felt slower.

 

[Mintona]

Passed through the diveunder this morning on a HC service. How much time is lost using the diveunder vs not using it? Not a huge amount obviously but it felt slower.

The linespeed on the up relief is 60/80. The linespeed through the dive under is 60/80, albeit it with a 50/75 speed on the turnout junction at the end of the road. You probably wouldn't notice the 5mph drop at the end, so you were probably on cautionary signals.

 

[QueensCurve]

The linespeed on the up relief is 60/80. The linespeed through the dive under is 60/80, albeit it with a 50/75 speed on the turnout junction at the end of the road. You probably wouldn't notice the 5mph drop at the end, so you were probably on cautionary signals.

I will confess to being slightly disappointed the diveunder isn't the "normal" route and is rather the turnout.

 

[II]

Passed through the diveunder this morning on a HC service. How much time is lost using the diveunder vs not using it? Not a huge amount obviously but it felt slower.

There's a 50mph Temporary Speed Restriction through the diveunder which will probably last a week or two, after which it will take the same time via either route.

The 5mph speed reduction to 75mph at the end of it won't have any impact on the vast majority of trains that have called at Ealing as they won't have reached 80mph by that point anyway.

 

[Chris125]

The linespeed on the up relief is 60/80. The linespeed through the dive under is 60/80, albeit it with a 50/75 speed on the turnout junction at the end of the road. You probably wouldn't notice the 5mph drop at the end, so you were probably on cautionary signals.

If there's no real difference in linespeed why didn't they just permanently re-route the Relief through the diveunder and avoid the extra pointwork?

 

[II]

If there's no real difference in linespeed why didn't they just permanently re-route the Relief through the diveunder and avoid the extra pointwork?

I guess it was a case of the track and signals already being there and a fair bit of the track still being needed to access Acton Yard and the Goods Loops. Also it gives a chance to regulate trains, so one up train could in theory be held in the diveunder whilst another overtakes it.

Finally, any freight heading towards the Up Poplar via Acton Main Line station would be best avoiding the steep 1 in 40 and 1 in 50 gradients of the diveunder. Currently all freight and HEx units are barred from using it anyway.

 

[jyte]

I guess it was a case of the track and signals already being there and a fair bit of the track still being needed to access Acton Yard and the Goods Loops. Also it gives a chance to regulate trains, so one up train could in theory be held in the diveunder whilst another overtakes it.

Finally, any freight heading towards the Up Poplar via Acton Main Line station would be best avoiding the steep 1 in 40 and 1 in 50 gradients of the diveunder. Currently all freight and HEx units are barred from using it anyway.

Why can't HEx units use it?
That seems odd.

 

[II]

Why can't HEx units use it?
That seems odd.

Worries about the suspension bottoming out I believe. There are a few worries over Turbos using it at full speed. Hopefully both fears won't be realised and any bars are only temporary.

 

[snowball]

Press release and video of bridge replacements in Monmouthshire:

http://www.networkrailmediacentre.c...aration-for-railway-electrification-continues

Stunning new timelapse has captured the demolition of three Monmouthshire bridges as upgrade work to electrify the South Wales Mainline continues, as part of Network Rail’s Railway Upgrade Plan.

The footage shows the demolition of Llandevenny, Rogiet and Huggets road bridges, which took place over the festive period. The timelapse also shows a new bridge deck being lifted into place at Llandevenny and elements of the new bridge piers installed at Huggets road bridge.

 

[Taunton]

Worries about the suspension bottoming out I believe. There are a few worries over Turbos using it at full speed.

Are we not capable of designing ANYTHING nowadays that gets delivered without basic problems?

 

[deltic08]

Are we not capable of designing ANYTHING nowadays that gets delivered without basic problems?

I thought the same. Probably that we are always trying to squeeze a quart into a pint pot now being such a small congested Country particularly in the Southeast.

 

[Nippy]

Also it gives a chance to regulate trains, so one up train could in theory be held in the diveunder whilst another overtakes it.

No chance of that, the signal into the dive under won't clear until the signal exiting the dive under is off.
--- old post above --- --- new post below ---

If there's no real difference in linespeed why didn't they just permanently re-route the Relief through the diveunder and avoid the extra pointwork?

You would still need the points access Acton Yard from the Up Relief though.

 

[QueensCurve]

I guess it was a case of the track and signals already being there and a fair bit of the track still being needed to access Acton Yard and the Goods Loops. Also it gives a chance to regulate trains, so one up train could in theory be held in the diveunder whilst another overtakes it.

Finally, any freight heading towards the Up Poplar via Acton Main Line station would be best avoiding the steep 1 in 40 and 1 in 50 gradients of the diveunder. Currently all freight and HEx units are barred from using it anyway.

The Up Relief could have been routed via the diveunder while retaining the former Up Relief as the turnout route. This would have allowed regulation/overtaking while providing the fastest route for passenger trains via diveunder.

 

[Peter Mugridge]

No chance of that, the signal into the dive under won't clear until the signal exiting the dive under is off.

Is this to avoid the risk of something stalling down there and being unable to climb out again?

 

[Taunton]

It seems to be a new fashion to construct new infrastructure which is not used all the time. Apparently the new flyover at Hitchin is the same, Cambridge fast services still regularly weave slowly across the old junction instead of taking the flyover, and up fast services can still be delayed by these.

 

[mr_jrt]

It seems to be a new fashion to construct new infrastructure which is not used all the time. Apparently the new flyover at Hitchin is the same, Cambridge fast services still regularly weave slowly across the old junction instead of taking the flyover, and up fast services can still be delayed by these.

I think the problem there is the penny pinching coupled with the aversion to even the slightest temporary disruption.

Had they built the flyover at Hitchin between the slow and the fast lines then there would be no issue as either could access it without conflict, but as it can only be accessed from the slows, and the Cambridge fasts need to access it, unless the slows are clear the fast services have to (if you excuse the ironic pun) pointlessly weave across as before.

 

[Nippy]

Is this to avoid the risk of something stalling down there and being unable to climb out again?

Probably.

 

[edwin_m]

I think the problem there is the penny pinching coupled with the aversion to even the slightest temporary disruption.

Had they built the flyover at Hitchin between the slow and the fast lines then there would be no issue as either could access it without conflict, but as it can only be accessed from the slows, and the Cambridge fasts need to access it, unless the slows are clear the fast services have to (if you excuse the ironic pun) pointlessly weave across as before.

The flyover diverges west just after the turnout to re-cross the main line at a relatively acute angle. If it had been between the fast and the slow lines, it would have had to rise up between those tracks, so following the path of the ECML, before crossing the tracks either left or right at a very shallow angle. This would have been a lot more expensive and possibly difficult to accommodate north of the station.

In terms of regulation I imagine a fast will use the flyover if there is an Up train approaching from Peterborough direction and the Down Slow is free for it to weave across. Otherwise the flat junction is probably quicker.

 

[158756]

I note that the latest CP5 enhancements update for electrification from Maidenhead to Cardiff and Newbury lists 'infrastructure ready for use' as 2017 or 2018, but 'first electric train' as CP6.

This seems rather strange if some sections (Maidenhead-Didcot ?) are already well on the way. Has this always been the target date, and given the existence of the bi-modes, surely some of the wires will be used when ready, even if they aren't ready all the way to Cardiff?

 

[absolutelymilk]

I note that the latest CP5 enhancements update for electrification from Maidenhead to Cardiff and Newbury lists 'infrastructure ready for use' as 2017 or 2018, but 'first electric train' as CP6.

Perhaps it means first purely electric train?

 

[Ianno87]

The Up Relief could have been routed via the diveunder while retaining the former Up Relief as the turnout route. This would have allowed regulation/overtaking while providing the fastest route for passenger trains via diveunder.

No, you would have to squeeze the Yard S&C to achieve that, and thus reduce the standage available in the Yard.

The benefit of the arrangement as built is that freighrs into the Yard initially go "straight on" before diverging. Thus they spend less time slowing down on, and blocking, the Uo Relief.

Plus I meant that the dive under could be built (largely) off line, rather than being hemmed in (for a phase) between a relocated Up Relief and the Down Relief, making construction access more difficult.

 

[HowardGWR]

I note that the latest CP5 enhancements update for electrification from Maidenhead to Cardiff and Newbury lists 'infrastructure ready for use' as 2017 or 2018, but 'first electric train' as CP6.

This seems rather strange if some sections (Maidenhead-Didcot ?) are already well on the way. Has this always been the target date, and given the existence of the bi-modes, surely some of the wires will be used when ready, even if they aren't ready all the way to Cardiff?

This is from RTM January 2016.

Sir Peter Hendy has revealed the completion dates of each element of the delayed Great Western Main Line electrification programme in an updated report today (22 January).
All elements of the programme will only start seeing electric trains running in CP6 (2019-2024), but the dates set for infrastructure authorisation are:
Maidenhead to Didcot: December 2017
Didcot to Wootton Bassett Junction: December 2018
Wootton Bassett Junction to Bristol Parkway: December 2018
Reading to Newbury: December 2018
Bristol Parkway to Cardiff: December 2018
Didcot to Oxford: June 2019
Wootton Bassett Junction to Bristol Temple Meads: February 2019-April 2020
Filton Bank: Early CP6

Thus a start date for Cardiff through all-electric services could never be before 2019, even if that plan were achieved. CP6 is from 2019 to 2024.

 

[II]

No chance of that, the signal into the dive under won't clear until the signal exiting the dive under is off.

Fair point. How about the other way round though? A train regulated on the up relief whilst something passes it on the dive under.

 

[Taunton]

I think the problem there is the penny pinching coupled with the aversion to even the slightest temporary disruption.

I think it was quite reasonable to impose penalty payments on upgrade works, as this was intended as an incentive to NR to perform the works as quickly and efficiently as possible, rather than saying "we'll close the line for three years, that will be convenient to us", and also co-ordinating works for track, signalling, civils, electrification, etc, instead of each devising their own separate closures, all the while causing ongoing disruption to existing users.

Unfortunately they have allowed what was intended as an incentive to the engineers to come back into the basic designs, to the extent that the fundamentals of the permanent design can be compromised. The whole idea was to get the engineers to speed up, not the designers to slow down.

 

[davetheguard]

This is from RTM January 2016.

Sir Peter Hendy has revealed the completion dates of each element of the delayed Great Western Main Line electrification programme in an updated report today (22 January).
All elements of the programme will only start seeing electric trains running in CP6 (2019-2024), but the dates set for infrastructure authorisation are:
Maidenhead to Didcot: December 2017
Didcot to Wootton Bassett Junction: December 2018
Wootton Bassett Junction to Bristol Parkway: December 2018
Reading to Newbury: December 2018
Bristol Parkway to Cardiff: December 2018
Didcot to Oxford: June 2019
Wootton Bassett Junction to Bristol Temple Meads: February 2019-April 2020
Filton Bank: Early CP6

Thus a start date for Cardiff through all-electric services could never be before 2019, even if that plan were achieved. CP6 is from 2019 to 2024.

Good to see proper dates again against Didcot - Oxford; Bristol via Bath. I had begun to fear that they might not happen at all.