Great Western Electrification Progress

[Banana]

Normal HST speeds according to a GWR insider involved with IET introduction posting elsewhere. Apparently westbound IETs running on AC reach 100mph by Acton and 125mph just after Hanwell (compared to HSTs which reach 125mph by Hayes). This is on the original BR OLE, which has been beefed up quite a bit over recent months.

How strange. The 125 permanent speed limit has started for the last 25 years on the Main Down just after Acton Main Line.

 

[Nippy]

Yes, but the trains can't accelerate from 100mph until they get to Acton.....

 

[Sean Emmett]

And the rate of acceleration on electric is determined by a rather complicated graph in the DfT tender document, presumably to avoid them sucking all the juice out of the overhead.

Remember that in the 1950s there was effectively no speed limit between Didcot and Swindon. But that didn't mean the Castles travelled at warp speed. Ye cannae change the laws of physics.

 

[snowball]

There are a couple of pages on Steventon Bridge as part of Roger Ford's column in the new Modern Railways, pp. 26-7.

 

[jimm]

Lots of steelwork in evidence at South Marston, just east of Swindon, in pictures taken yesterday by Martin Loader

http://hondawanderer.com/Recent_Additions.htm

 

[edwin_m]

There are a couple of pages on Steventon Bridge as part of Roger Ford's column in the new Modern Railways, pp. 26-7.

For those that haven't seen it, it suggests that actually the diesels would have to be powered up for quite a long distance just for this section, though it doesn't make clear whether would include Didcot stoppers having their diesels running when in the station.

It also completely ignores the possibility of dropping the pan and coasting through the affected section. This is fairly routine nowadays for planned and unplanned OLE works, the gap can't be more than a few hundred metres and gradients are famously very gentle. I can't think why it wouldn't work here with the diesels being started only in the very unusual even of a train being stranded in the gap.

 

[GRALISTAIR]

Stranded in the Grayling gap has a nice ring to it.

Those overheads sure look substantial no wonder it is over budget

 

[Wilts Wanderer]

Remember that prior to the Ladbroke Grove accident, the speed limit from pretty much the platform ends at Paddington was 80mph, rising to 100mph at Kensal Green. This was tailored to the HST acceleration graph, meaning a continuous notch 5 power application could be made from Royal Oak taking you right up to linespeed without break.

It is now 50mph to Kensal Green, which adds about 2 mins to the Paddington-Reading journey, additionally the running brake test is performed at 40mph rather than above 100mph which adds yet more time. Then allow for defensive / efficient driving techniques, and the extra Mk3 in the formations, ATP (and adherence to the 125mph limit!) and you can see why Padd-Reading in 18 mins can't possibly be achievable any more.

 

[HowardGWR]

Stranded in the Grayling gap has a nice ring to it.

Those overheads sure look substantial no wonder it is over budget

I doubt it. The materials cost factor was not mentioned by the audit report that was produced. In other words, one assumes these costs were correctly budgeted.

 

[absolutelymilk]

Remember that prior to the Ladbroke Grove accident, the speed limit from pretty much the platform ends at Paddington was 80mph, rising to 100mph at Kensal Green. This was tailored to the HST acceleration graph, meaning a continuous notch 5 power application could be made from Royal Oak taking you right up to linespeed without break.

It is now 50mph to Kensal Green, which adds about 2 mins to the Paddington-Reading journey

Why was there a decrease in the speed limit to Kensal Green?

 

[MarkyT]

There are a couple of pages on Steventon Bridge as part of Roger Ford's column in the new Modern Railways, pp. 26-7.

Not read that yet. Seems to me there's a lot of concern from local businesses in the High Street who see lost trade from south of the railway due to the extended road closure involved. My suggestion would be a temporary free car park on the south side during the works in an adjacent field. Using the temporary foot crossing, no part of the High Street would be more than about a 400m walk from there. Taking it further, perhaps certain affected food businesses might be allowed to set up temporary kiosk outlets in such a car park area. Just trying to think outside the box! I guess the nearby level crossings limit the amount of vertical trackbed adjustment possible. Frankly, the bridge does not appear sufficiently unusual to warrant exceptional measures to retain it.

 

[LNW-GW Joint]

I doubt it. The materials cost factor was not mentioned by the audit report that was produced. In other words, one assumes these costs were correctly budgeted.

Only if you assume that massive piled structures are required for the catenary on a simple 2-track railway.
No attempt seems to have been made to simplify the structures outside the 4-track area, or where less than 140mph is possible.
HS1 isn't like that, and it handles 300km/h.
Roger Ford has another article on this in November Modern Railways, and discusses the Master Series that will replace Series 1 and 2 OHLE design.
It will apparently be used on Bedford-Kettering-Corby.

 

[Peter Mugridge]

Why was there a decrease in the speed limit to Kensal Green?

I was under the impression that it was to give more time for signal sighting after the collision was found to be partly a result of poor visibility of SN109 on the day.

 

[HowardGWR]

Only if you assume that massive piled structures are required for the catenary on a simple 2-track railway.
No attempt seems to have been made to simplify the structures outside the 4-track area, or where less than 140mph is possible.
HS1 isn't like that, and it handles 300km/h.
Roger Ford has another article on this in November Modern Railways, and discusses the Master Series that will replace Series 1 and 2 OHLE design.
It will apparently be used on Bedford-Kettering-Corby.

That isn't the point I was discussing. I don't think the materials costs of the structures were underestimated and thus account for the overrun on costs, since there is no evidence that these structures were changed in design during the project, or that the supplier increased his prices. That they were OTT for the job in hand is the point which you are addressing. That remains to be seen, by the way, as the future years of use shew us if they were indeed OTT in specification.

AIUI, the cost overrun was partly due to the unexpected and thus unbudgeted difficulty in erecting the structures. Undocumented cable locations was one reason given and the inability to use planned automation of erection was also mentioned.

 

[edwin_m]

That isn't the point I was discussing. I don't think the materials costs of the structures were underestimated and thus account for the overrun on costs, since there is no evidence that these structures were changed in design during the project, or that the supplier increased his prices. That they were OTT for the job in hand is the point which you are addressing. That remains to be seen, by the way, as the future years of use shew us if they were indeed OTT in specification.

AIUI, the cost overrun was partly due to the unexpected and thus unbudgeted difficulty in erecting the structures. Undocumented cable locations was one reason given and the inability to use planned automation of erection was also mentioned.

It's possible that the very early estimates on which the Government gave its go-ahead were based on relatively crude unit costs such as indexing the cost of the ECML project up to current values. The cost may then have crept up later as different equipment and methods of working were selected based on the higher specification and today's standards (open to question how necessary this was). Further overruns then resulted because the efficient processes that were assumed turned out not to be achievable. Without access to internal NR and DfT figures it's very hard to tell which of these factors contributed how much to the overspend - but I hope someone official is trying to do that.

To my mind the critical question is: if another scheme was started in the future, properly planned and learning from the mistakes of GW and other current projects, how much would it cost? If it can't be got down close to the cost of the ECML in real terms (as Modern Railways claims is being achieved in Denmark) then the case for future electrification is poor.

 

[D1009]

Remember that prior to the Ladbroke Grove accident, the speed limit from pretty much the platform ends at Paddington was 80mph, rising to 100mph at Kensal Green. This was tailored to the HST acceleration graph, meaning a continuous notch 5 power application could be made from Royal Oak taking you right up to linespeed without break.

It is now 50mph to Kensal Green, which adds about 2 mins to the Paddington-Reading journey, additionally the running brake test is performed at 40mph rather than above 100mph which adds yet more time. Then allow for defensive / efficient driving techniques, and the extra Mk3 in the formations, ATP (and adherence to the 125mph limit!) and you can see why Padd-Reading in 18 mins can't possibly be achievable any more.

Was 18 mins ever achievable then? I've been around since well before the HSTs came on the scene, and can't remember ever doing it in less than 21.

 

[Peter Mugridge]

Was 18 mins ever achievable then? I've been around since well before the HSTs came on the scene, and can't remember ever doing it in less than 21.

I had an 18 minute start to stop from Paddington to Reading once; one other person who is a member of this forum was on board with me and probably remembers that run himself. What was even more striking is it had a slow start and then crawled in to Reading for the last couple of miles as there were caution signals ahead of us!

On 16th October, the first IET off Paddington, 07.00 to Bristol... what the RTT timings showing it reached Reading in 25 minutes don't show you is that this was again held up be cautions on the approach to Reading ( we had caught up on a Cotswold service formed by 180 103 ); had we had a clear run in to Reading we would certainly have achieved a 20 minute start to stop time.

 

[MarkyT]

Was 18 mins ever achievable then? I've been around since well before the HSTs came on the scene, and can't remember ever doing it in less than 21.

It's 36 miles so 18 minutes requires an AVERAGE speed of 120MPH. Start to stop, there's no way that could ever have been possible within speed limits. Start to pass or vice versa just maybe occasionally with a little leeway on speed for a publicity run and a fair wind. Was 18 minutes ever timetabled?

 

[Peter Mugridge]

Never timetabled, no.

 

[MarkyT]

Never timetabled, no.

Thanks. I expect like most modern electric trains, IETs will be a little more sprightly than HSTs, when on electric power at least. They've got to fit in with 4tph 100MPH HEXs as far as Heathrow Airport Junction though, so for capacity reasons I expect on full fleet introduction they won't be timed to exceed this until beyond there.

 

[D1009]

It's 36 miles so 18 minutes requires an AVERAGE speed of 120MPH. Start to stop, there's no way that could ever have been possible within speed limits. Start to pass or vice versa just maybe occasionally with a little leeway on speed for a publicity run and a fair wind. Was 18 minutes ever timetabled?

Never timetabled, no.

That's because as above, it wasn't possible. I recall the scheduled time to Reading in 1976 was 22 minutes, and it increased to 23 when the 2+8s came in. There have been several reports on the class 800 thread already of IETs arriving at Reading in less than 23 minutes, in fact the one run I've had from Paddington did it in 23 despite departing from the unelectrified platform 2 at Paddington, meaning we ran slowly as the pantographs were raised en route to Ladbroke Grove, and also a slightly restricted approach to platform 8 at Reading. Once it is electric all the way I'd have thought 22 mins easily possible once again.

 

[InOban]

BTW, did last weekend's closure complete all the previously uncompleted tasks in the Reading area?

 

[Schweir]

Does anyone know if it is the 14:29, or the 15:29, from Swansea to London Paddington which is the IET?

 

[Mordac]

BTW, did last weekend's closure complete all the previously uncompleted tasks in the Reading area?

It's been reported elsewhere that it fried some expensive piece of equipment...

 

[Wilts Wanderer]

That's because as above, it wasn't possible. I recall the scheduled time to Reading in 1976 was 22 minutes, and it increased to 23 when the 2+8s came in. There have been several reports on the class 800 thread already of IETs arriving at Reading in less than 23 minutes, in fact the one run I've had from Paddington did it in 23 despite departing from the unelectrified platform 2 at Paddington, meaning we ran slowly as the pantographs were raised en route to Ladbroke Grove, and also a slightly restricted approach to platform 8 at Reading. Once it is electric all the way I'd have thought 22 mins easily possible once again.

It wasn't possible within the speed limits no, but there are well-documented and verified accounts of HSTs sustaining speeds in excess of 135mph to achieve the seemingly impossible. If you've never heard of the '140 Club' just ask a retired Paddington driver!

I personally have timed a GWR HST (2+8, MTU engines) achieving Padd-Reading in 22 mins 30 secs, and ATP guarantees a max speed of 127mph. So I'm not surprised if 800s can achieve sub-20 min timings when the conditions suit.

 

[D1009]

It wasn't possible within the speed limits no, but there are well-documented and verified accounts of HSTs sustaining speeds in excess of 135mph to achieve the seemingly impossible. If you've never heard of the '140 Club' just ask a retired Paddington driver!

I personally have timed a GWR HST (2+8, MTU engines) achieving Padd-Reading in 22 mins 30 secs, and ATPguarantees a max speed of 127mph. So I'm not surprised if 800s can achieve sub-20 min timings when the conditions suit.

Yes, and these stories tend to be exaggerated over the years. On a trip from Paddington to Reading you would not get to 135 for long, but mathematically 20 miles at 125 is 9 mins 36 secs. 20 miles at 135 is 8 mins 53 secs, so the gain with the excess speed would be much less than a minute.

 

[Sean Emmett]

FWIW the Railway Performance Society archives have nearly 5,000 runs betw PAD and RDG, fastest 20m 45s and another at 20m 49s published in the Milepost magazine.

This was early 80s and conjecture was that 20m 30s was quickest possible with kit and infrastructure of the time.

With IET I have recorded 22m 26s, which is quicker than anything in RPS archive since 1999.

But 18 mins? Whose cider you on?

 

[Railperf]

It is handy now that the speed limit through Reading platform 9 is now 95mph for an HST /IET rather than the previous 50mph limit brought in before the remodelling. However, all the westbound trains I have used seem to approach the Reading station stop on restrictive aspects - usually the platform departure signal is at red. And that seems to cause drivers to approach the station far more cautiously than if the departure signal from Reading was clear.

 

[HowardGWR]

Is it also 95mph for platform 10 (the main up line presumably, or is that 8)?

 

[Railperf]

Yes, platform 10 is also 95mph for HST