Cost of bi-modes v's wiring-up

[O L Leigh]

You don't think that the Government has strategic vision, yet you are against the option that would allow us to improve things without requiring such forward thinking Government.

I am...? I think you'd better go back and review my contributions to the discussion so far.

 

[Grumpy Git]

................................. the massive structures that GWEP have installed and priced it out of the market is the issue.

Why are the overhead gantries built solid enough to support the weight of Queen Mary II on this route? I've just looked at the ones in Newbury on Google Earth and they are massive in comparison to what (for instance) the German railways use (i.e. a lightweight lattice pylon construction). Were the designers on some sort of kick-back from the steel suppliers?

 

[Nottingham59]

The Network Rail assured estimate

I would hope that NR has got good estimates by now on the costs of electrification. But what assumptions do their calculations make about the volume of passengers and the value of their time over the next 60 years? And what assumptions about diversion of long-distance business passenger flows onto the HS2 Eastern Leg? Those numbers are critical to the social benefits that have to be assumed in calculating BCR. And if NR have excluded the possibility of diversion onto HS2, because that HS2(East) spending has not been confirmed yet, then the BCR calculations for the MML are meaningless.

 

[Annetts key]

Why are the overhead gantries built solid enough to support the weight of Queen Mary II on this route? I've just looked at the ones in Newbury on Google Earth and they are massive in comparison to what (for instance) the German railways use (i.e. a lightweight lattice pylon construction). Were the designers on some sort of kick-back from the steel suppliers?

Like these you mean...

 

[Grumpy Git]

Yes.

 

[gg1]

Like these you mean...
View attachment 96260

That's some especially ugly OHLE there.

 

[ohgoditsjames]

Curious as to why wooden poles aren’t an option. The DNO I work for use wood supports for voltages all the way up to 66kV.

 

[Nicholas Lewis]

Curious as to why wooden poles aren’t an option. The DNO I work for use wood supports for voltages all the way up to 66kV.

They are used on lower speed lines in Europe but guess main issue would be the maintaining contact wire geometry and the forces that are exerted on the wire compared to DNO where conductors are just naturally hang between poles.

 

[ohgoditsjames]

They are used on lower speed lines in Europe but guess main issue would be the maintaining contact wire geometry and the forces that are exerted on the wire compared to DNO where conductors are just naturally hang between poles.

Yes I can see the tension being a problem. The weight of the conductor itself wouldn’t pose a problem, the conductors we use for 66kV are larger (the specs can vary greatly) and there’s pretty much always at least 3 conductors, 1 per phase. I do know of areas where a wood pole has carried 2 separate three phase circuits without a problem.

Could be an option for the commuter routes I suppose.

 

[Grumpy Git]

As an aside, in the last 12 months the average price of mild steel has increased by approx. 300% (and we are struggling to maintain an independent steel industry)!

 

[Class 170101]

It will also depend on how money is spent.

Take a wiring scheme that many on this board want;
Kettering to Nottingham and to Sheffield via Derby

This has up four electric services per hour to East Midlands Parkway and two each to both routes thereafter. However there are other services using this route which could make the wires more valuable than 4tph, Leicester to Lincoln / Grimsby / Cleethorpes
Newark Castle to Crewe, Nottingham to Matlock, Nottingham to Birmingham New Street and Nottingham to Cardiff.

Should the EMR listed above either be split to use electric trains on the electrified sections or should become bi-mode trains (they cost money to procure), or perhaps should routes be changed to fit where the wires are? So perhaps Nottingham to New Street and Cardiff services are diverted to Matlock and Crewe (therefore remaining diesel) and a local Derby to Nottingham service provided by EMUs The same to the East, EMUs Leicester to Nottingham with diesels east of Nottingham linking Newark Castle with Worksop.

I don't think its therefore as simple as a choice between Bi-modes or wires.

 

[AM9]

Yes I can see the tension being a problem. The weight of the conductor itself wouldn’t pose a problem, the conductors we use for 66kV are larger (the specs can vary greatly) and there’s pretty much always at least 3 conductors, 1 per phase. I do know of areas where a wood pole has carried 2 separate three phase circuits without a problem.

Could be an option for the commuter routes I suppose.

Most 'commuter routes', i.e outer suburban routes, not metro lines within cities, are required to support 100mph running, which not only calls for high static wire tension, but also very tight controls on registration under multiple pantograph loadings and in windy weather. DNO and ESO lines usually have fixed tension conductors with much deeper sagging to allow for a large thermal variation.

25kV isn't the gold standard but we've managed to over engineer the product we installed in the 1960's over 1000's of miles which is still standing up doing its job to the massive structures that GWEP have installed and priced it out of the market is the issue. ...

I disagree. The original early OLE electrification schemes in the UK (excepting the LB&SCR short-lived scheme) have been built with very substantial structures. Look at those of the two LNER routes,:
1) the GEML to Southend Victoria
2) the Manchester to Sheffield line via the Woodhead tunnel
Both of these were to carry heavy 1500VDC copper catenaries but at speeds around 70-80mph max. The gantries were very well specified and lasted well into the 21st century, - thats over 70 years of heavy service, especially over the GEML tracks. In the '80s, the accountants helped to design the OLE on the MML south and the ECML, lots of pretty headspans and lightweight supports which has given appalling service at high speeds over about 40 years.
Basically, you get what you pay for, in the case of OLE, low capital material cost, higher cost of ownership, vs higher capital material cost, lower through-life cost. The actual GWEP cost suffered more from the disruption caused by digging up buried hidden signal cables than the additional cost of better masts and portals required for 125mph running.

 

[Bald Rick]

Both of these were to carry heavy 1500VDC copper catenaries but at speeds around 70-80mph max. The gantries were very well specified and lasted well into the 21st century, - thats over 70 years of heavy service, especially over the GEML tracks. In the '80s, the accountants helped to design the OLE on the MML south and the ECML, lots of pretty headspans and lightweight supports which has given appalling service at high speeds over about 40 years.

One thing I’ve learned, the hard way, through my career is that the single greatest factor for the reliability of the OLE system is how well it is maintained, and not its design.

Clearly, some OLE systems are easier (and thus cheaper) to maintain than others. But the MML OLE is, actually, very reliable - simply because Bedford OLE do such a great job and keep on top of their defects.

(I realise this could be the Bald Rick commentator’s curse, and I fully expect the whole lot to come down at Radlett or somewhere equally critical in the next couple of hours).

 

[Annetts key]

(I realise this could be the Bald Rick commentator’s curse, and I fully expect the whole lot to come down at Radlett or somewhere equally critical in the next couple of hours).

Best get some coffee substitute and with sugar substitute and hot water ready then...

 

[Ken H]

Why they didnt go for new locos to drag straight electrics off the wires I dont know. Not dragging a load of diesel kit for most of the day would have been sensible. And enough horses could have been installed in the loco.

 

[JamesT]

Why they didnt go for new locos to drag straight electrics off the wires I dont know. Not dragging a load of diesel kit for most of the day would have been sensible. And enough horses could have been installed in the loco.

As has been mentioned in the many threads on the 80x before, you're adding a risk of delay for coupling and uncoupling the locomotive. A heavy locomotive will also hammer the track far more than the distributed traction of the 80x. It's noticeable that the only ToC that bothers with traction changes is the sleeper, who have hours of wiggle in their timetable to manage it.

 

[Energy]

Why they didnt go for new locos to drag straight electrics off the wires I dont know. Not dragging a load of diesel kit for most of the day would have been sensible. And enough horses could have been installed in the loco.

Locomotives are very expensive in track access charges (high axle weight), somebody worked out a while ago that a 68+5mk5as is about the same in cost (or even slightly more) than a 6 car 185, which are heavy as MUs go.

New diesel locomotives for the UK is difficult due to environmental issues, the 68s no longer comply and there isn't a lot of space left inside them for the extra enviromental stuff. I think the extra enviromental stuff may also cause cooling issues although I'm not sure.

Coupling also adds time at stations and requires more staff than the driver pushing a button.

 

[Annetts key]

As has been mentioned in the many threads on the 80x before, you're adding a risk of delay for coupling and uncoupling the locomotive. A heavy locomotive will also hammer the track far more than the distributed traction of the 80x. It's noticeable that the only ToC that bothers with traction changes is the sleeper, who have hours of wiggle in their timetable to manage it.

But this thing of no longer attaching/detaching a locomotive to/from the coaches of an in service train is relatively recent. It’s not that long ago when locos would regularly get swapped. Where I am, because there was not enough DMUs, so the railway continued to use locos (normally 47’s) and mark 2 stock. With the resulting run round of the loco at each end of the run (at the terminating station, such as Bristol T.M.).

Just like a pit stop in formula one, of course attaching/detaching a locomotive can go wrong. But if it’s practiced, and done very regularly, the vast majority of the time, there should be very few problems.

And it’s not like the coupling/uncoupling of DMUs ever goes wrong...

Please note, my comments above do not necessarily mean that I am against bi-modes.

 

[AM9]

One thing I’ve learned, the hard way, through my career is that the single greatest factor for the reliability of the OLE system is how well it is maintained, and not its design.

Clearly, some OLE systems are easier (and thus cheaper) to maintain than others. But the MML OLE is, actually, very reliable - simply because Bedford OLE do such a great job and keep on top of their defects.

(I realise this could be the Bald Rick commentator’s curse, and I fully expect the whole lot to come down at Radlett or somewhere equally critical in the next couple of hours).

My comment was in response to the post(s) that presume the GWEP overspent because the OLE has substantial portals, cantilevers and masts, - much more material than was needed in their opinion. In actual cost terms, the large cross section portals and other steelwork form a small part of the overall material cost and an even smaller component in the whole project budget, even though the supplier was chosen on quality rather than up front price.
Of course the reliability (and availability) of OLE is highly dependant on effective maintenance regimes, but the (relatively) low cost systems used on the '70s and '80s electrifications were not only more prone to random failures, but when such failures do occur, the interdependance of the mechanical support arrangements across multiple tracks (thinking specifically headspans here), result in far more widespread collateral damage and usually total line disruption. A single dropper failure on a high speed line can result in total route closure for two or more days as there is little resilience in the support of the other tracks once the 'cats cradle' has been disturbed.
Apologies for digressing from the strict original topic but the type of OLE installation can have a major impact on the usability of the track below whether the trains it supplies have independant traction power or not.

 

[Energy]

Just like a pit stop in formula one, of course attaching/detaching a locomotive can go wrong. But if it’s practiced, and done very regularly, the vast majority of the time, there should be very few problems.

But we can still do away with it entirely with bimodes. Plus there is still the problem of high track access charges for locos.

 

[Annetts key]

If we are taking the increased amount of track maintenance that results if locomotives are used compared to lighter multiple unit trains, how much difference does a high speed bi-mode make when compared to the equivalent high speed OHL electric only multiple unit?

As a bi-mode is carrying multiple diesel engines, generators, cooling systems, control gear, fuel tanks complete with gallons of fuel compared to the much simpler OHL electric only multiple unit.

And is the increased amount of track maintenance significant on a line that uses diesel locomotives to pull ‘electric’ trains if the freight services are still hauled by diesel locomotives?

Certainly, class 43 HST power cars definitely give point work some hammering. But then so do the freights. Especially those with a load of stone/ballast or the china clay train, which definitely cause increased wear to the track (rails, fixings, sleepers as well as ballast).

Back to the OHL structures. One question I have, is why two masts (vertical support ’posts’) are needed on plain line sections (for example, as shown in the photo I posted earlier in this topic, although in this area, the up and down lines are at different heights, due to the different gradients through the separate single bore tunnels).

I agree that the actual cost of the steel structures are not a significant factor that caused the Western scheme to blow the budget. But if there were less foundation works needed, because higher strength masts were used to provide the supports for two lines, instead of separate masts for each line, would that have changed the costs by any significant amount?

 

[hwl]

My comment was in response to the post(s) that presume the GWEP overspent because the OLE has substantial portals, cantilevers and masts, - much more material than was needed in their opinion. In actual cost terms, the large cross section portals and other steelwork form a small part of the overall material cost and an even smaller component in the whole project budget, even though the supplier was chosen on quality rather than up front price.
Of course the reliability (and availability) of OLE is highly dependant on effective maintenance regimes, but the (relatively) low cost systems used on the '70s and '80s electrifications were not only more prone to random failures, but when such failures do occur, the interdependance of the mechanical support arrangements across multiple tracks (thinking specifically headspans here), result in far more widespread collateral damage and usually total line disruption. A single dropper failure on a high speed line can result in total route closure for two or more days as there is little resilience in the support of the other tracks once the 'cats cradle' has been disturbed.
Apologies for digressing from the strict original topic but the type of OLE installation can have a major impact on the usability of the track below whether the trains it supplies have independent traction power or not.

A large amount of the cost overrun was caused by continually trying to meet impossible deadline, acknowledging that early and delaying HST retirement by 2years would have saved lots.

 

[Ken H]

If we are taking the increased amount of track maintenance that results if locomotives are used compared to lighter multiple unit trains, how much difference does a high speed bi-mode make when compared to the equivalent high speed OHL electric only multiple unit?

As a bi-mode is carrying multiple diesel engines, generators, cooling systems, control gear, fuel tanks complete with gallons of fuel compared to the much simpler OHL electric only multiple unit.

And is the increased amount of track maintenance significant on a line that uses diesel locomotives to pull ‘electric’ trains if the freight services are still hauled by diesel locomotives?

Certainly, class 43 HST power cars definitely give point work some hammering. But then so do the freights. Especially those with a load of stone/ballast or the china clay train, which definitely cause increased wear to the track (rails, fixings, sleepers as well as ballast).

Back to the OHL structures. One question I have, is why two masts (vertical support ’posts’) are needed on plain line sections (for example, as shown in the photo I posted earlier in this topic, although in this area, the up and down lines are at different heights, due to the different gradients through the separate single bore tunnels).

I agree that the actual cost of the steel structures are not a significant factor that caused the Western scheme to blow the budget. But if there were less foundation works needed, because higher strength masts were used to provide the supports for two lines, instead of separate masts for each line, would that have changed the costs by any significant amount?

Didnt the GW electrification come into problems sinking the piles for the masts? Not only because of buried cabling, but many didnt sink as easily as the design suggested, requiring 2nd visits of the piling train. UU railway have been doing piled masts since ECML electrification. Why did GW have difficulty with this? Were the piles over specified?

 

[Energy]

If we are taking the increased amount of track maintenance that results if locomotives are used compared to lighter multiple unit trains, how much difference does a high speed bi-mode make when compared to the equivalent high speed OHL electric only multiple unit?

As a bi-mode is carrying multiple diesel engines, generators, cooling systems, control gear, fuel tanks complete with gallons of fuel compared to the much simpler OHL electric only multiple unit.

And is the increased amount of track maintenance significant on a line that uses diesel locomotives to pull ‘electric’ trains if the freight services are still hauled by diesel locomotives?

Certainly, class 43 HST power cars definitely give point work some hammering. But then so do the freights. Especially those with a load of stone/ballast or the china clay train, which definitely cause increased wear to the track (rails, fixings, sleepers as well as ballast).

The problem isn't the wear but the track access charges NR decide to charge, unpowered carriages will weight less so that will help to offset the cost of the weight of the locomotive but MUs usually work out to be cheaper in track access charges than a loco and carriages.

 

[Domh245]

Back to the OHL structures. One question I have, is why two masts (vertical support ’posts’) are needed on plain line sections (for example, as shown in the photo I posted earlier in this topic, although in this area, the up and down lines are at different heights, due to the different gradients through the separate single bore tunnels).

I agree that the actual cost of the steel structures are not a significant factor that caused the Western scheme to blow the budget. But if there were less foundation works needed, because higher strength masts were used to provide the supports for two lines, instead of separate masts for each line, would that have changed the costs by any significant amount?

I was under the impression that GWEP made extensive use of twin-track cantilevers wherever possible. Where single track cantilevers exist, it's usually because there was something preventing a TTC

 

[Annetts key]

Didnt the GW electrification come into problems sinking the piles for the masts? Not only because of buried cabling, but many didnt sink as easily as the design suggested, requiring 2nd visits of the piling train. UU railway have been doing piled masts since ECML electrification. Why did GW have difficulty with this? Were the piles over specified?

Most of the problems with the piling had nothing to do with buried signal and telecommunications cables, at least, not on the western end of the project where the relevant S&T engineering staff were actually asked to help.

BR Western Region did, prior to privatisation, have cable plans showing details of the where the signal and telecommunications cables were. As in the 1960s and 1970s, buried cable routes were common. Some of these records were missing however.

But since the 1980s, surface concrete troughing became the preferred method. Lineside signal cables typically only last about twenty to thirty-five years. Although lead sheathed signal and telecommunications cables (if not damaged) can last much, much longer. But cables of this type have not been installed since the 1970s.

So, as a result of various cable renewals over the years, the existing buried cables (if any) were either already redundant, or were known about (even if there exact location was not always accurate). Often, the only buried cables in use were telecommunications cables or 650V power cables (the former are very difficult to detect with a CAT (cable avoidance tool) scanner, the power cables are easy to detect).

The original plan had been for the signalling to be renewed prior to the piling. As part of this, the legacy telecommunications cables would also become redundant (the remaining services being carried by either the Network Rail Fixed Telecom Network (FTN) or via new telecommunications cables. Hence there would be no operational buried cables to hit...

I can’t comment about what happened on the earlier part of the scheme. But I will say that buried cables getting hit and cut or damaged during engineering works had been going on for many, many years before the electrification scheme came into being. So it was not new to the railway.

 

[Hellzapoppin]

All of the drawings for the cables you mentioned were and still are available but we’re never asked for. They show the original location based on the track position at the time of installation, if the track was slewed then the distances change. This is one of the reasons why trial holes were needed.

 

[tbtc]

Why they didnt go for new locos to drag straight electrics off the wires I dont know. Not dragging a load of diesel kit for most of the day would have been sensible. And enough horses could have been installed in the loco.

So (assuming that GWML electrification reaches Bristol and Oxford) that's...

• Loco at Newark for the Lincoln drag
• Loco at Doncaster for the Hull drag
• Loco at Leeds for the Harrogate drag
• Loco at York for the proposed Middlesbrough drag
• Loco at Newcastle for the Sunderland drag
• A handful of locos at Edinburgh for the Aberdeen/Stirling/ Inverness drags
• A handful of locos at Oxford for the Hereford drags (plus Banbury?)
• A handful of locos at Cardiff for the Swansea/ Pembrokeshire drags
• Lots of locos at Newbury (?) for the Devon/ Cornwall drags
• Loco at Bristol for the Weston drag

(apologies if I've missed any? I'm only including services that have bi-modes, so I'm not counting the pure-diesel GC services to Sunderland/ Bradford Interchange)

All those locos need specialist staff too, so you're going to have them sitting around for long periods

Plus the additional track damage caused by a heavyweight loco, rather than the (relatively) distributed weight of multiple units

Plus the problem of "running round" and all of the additional movements required at stations that have been rationalised for the modern era and no longer have the head shunts/ middle roads/ pointwork they had in the 1980s

Plus the reliability problems that Virgin had when they tried to operate the Holyhead services with 57s dragging 390s west of Crewe

Plus the operational headaches caused by long established diversions (e.g. when the ECML is shut north of Newcastle each October, the trains have to run via the unnelectrified Tyne Valley - similar problems with the "Joint" line through Lincolnshire and other routes), or just the not-uncommon events where the electrification fails but diesel trains can still run

Compared to that, having a handful of engines underneath the multiple unit seems a pretty small price to pay - in fact, given all of the superfluous things that we carry around on trains, it's just another thing on the list (e.g. as mentioned by another poster on the thread, trains only ever use the cab at one end yet we don't have a problem with the weight of a second cab)

Don't get me wrong - I love messy shunting moves - I grew up watching the coupling and splitting of services at 1980s Carstairs - I love a picture of an old loco dragging a modern train over something like Ribblehead - it's fun to see all of the complication - but it's a real operational headache, and we have a busy modern railway that can't accommodate all of this (e.g. does a loco occupy one of the handful of through platforms at Leeds whilst it waits in between Harrogate duties?)

 

[snowball]

Didnt the GW electrification come into problems sinking the piles for the masts? Not only because of buried cabling, but many didnt sink as easily as the design suggested, requiring 2nd visits of the piling train. UU railway have been doing piled masts since ECML electrification. Why did GW have difficulty with this? Were the piles over specified?

According to numerous articles I've read the piles were much longer than on previous generation schemes due to the method of calculation. I don't think they were more difficult to sink per metre than piles on previous schemes.