Midland Main Line Electrification

[caradoc]

I think the issue here is that the Canal line keeps the wire live under low-clearance bridges.  There is enough clearance for the local EMU fleets to operate but not enough for safe clearance to other stock.  The MML or other major route that carries a wide variet of stock couldn't adopt this approach, but it might be possible to have a short dead section where the wire is high enough to physically clear the roofs but not high enough for electrical clearances.  This obviously carries some risk of trains being stranded in the dead section, although a bi-mode could rescue itself by switching to diesel power. 

 

I think you're right Edwin_m.

 

Neutral sections near stations exist today, for example immediately on the Motherwell side of Rutherglen station on the Argyle Line, and immediately east of Longniddry station, and yes, trains do occasionally become stranded in the dead sections, most commonly during times of low rail adhesion. However it is not a frequent occurence, even though at Rutherglen the neutral section is very close to the platform, and on a sharp curve as well ! Maybe such a solution could be adopted at Leicester, although the length of the dead section might be an issue; Perhaps the stopping point for Up trains could be moved as far back along the platforms as possible ?

[DY444]

Are all these "risks" real risks, or just perceived ones?

 

How many have been injured with the current standards in place?

Will the new standards actually improve things, or is it just a box-ticking exercise?

 

They are almost certainly perceived.  The question was posed as to how many of the electrocutions which have occurred since 25KV first appeared in the UK would they have prevented.  The consensus appears to be that the answer is zero.  ALARP appears to have been another casualty of the mess the railway currently finds itself in.

[DY444]

Such a method was used to enable the Corkerhill/Paisley Canal route to be electrified (relatively) cheaply.

 

Are you sure?  I didn't think that structures had had insulation placed on their undersides on Paisley Canal to reduce the flash over risk.  I thought it merely used reduced clearances (as indeed does Thameslink through the core) with consequent severe restrictions on the electric traction types that can be accommodated (again as per Thameslink core). 

[Titan]

They are almost certainly perceived.  The question was posed as to how many of the electrocutions which have occurred since 25KV first appeared in the UK would they have prevented.  The consensus appears to be that the answer is zero.  ALARP appears to have been another casualty of the mess the railway currently finds itself in.

 

You are absolutely right of course. The problem is that it is perceived that over the last few years the risk has significantly increased. Trouble is with no statistical data to work with it is impossible to tell by how much. This creates a dilemma. If it is perceived that the risk is increasing, and nothing was done, then there will be a lot of explaining to do when someone does get injured/killed. It is also unwise to look at a history of no accidents as proof of safety, as sometimes it has been down to luck. Concord was a victim of this and there are plenty of others.

[Edwin_m]

You are absolutely right of course. The problem is that it is perceived that over the last few years the risk has significantly increased. Trouble is with no statistical data to work with it is impossible to tell by how much. This creates a dilemma. If it is perceived that the risk is increasing, and nothing was done, then there will be a lot of explaining to do when someone does get injured/killed. It is also unwise to look at a history of no accidents as proof of safety, as sometimes it has been down to luck. Concord was a victim of this and there are plenty of others.

Yes and no.  The number of occasions where a passenger has waited on a 25kV platform not compliant to the latest standard and managed to avoid electrocution must be way in excess of any events related to the small fleet of Concordes, and ought to be enough to demonstrate some statistical significance.  However the caveat is about whether the risk is increasing, for example due to people's average stature increasing in recent years and because of items such as foil balloons and selfie sticks.  I think the logical answer would be to provide the increased clearances wherever reasonably practicable but if existing bridges limit the wire height and aren't being re-built for other reasons then a lower clearance should be allowed on a generic basis without having to do detailed risk assesment each time.   This should be possible under Common Safety Method 2 which involves demonstrating equivalent to an existing comparable application. 

[caradoc]

Are you sure?  I didn't think that structures had had insulation placed on their undersides on Paisley Canal to reduce the flash over risk.  I thought it merely used reduced clearances (as indeed does Thameslink through the core) with consequent severe restrictions on the electric traction types that can be accommodated (again as per Thameslink core). 

 

I think we're both right DY444; Four bridges have the reduced clearance OLE but one does have what is termed an 'extended neutral section'.

 

Neutral sections have also been used before where there was no other feasible way of obtaining clearance between the OLE and a structure, for example on the Cathcart Circle between Queens Park and Pollokshields East, and at Tams Brig near Newton Junction, Ayr.

[RANGERS]

I think we're both right DY444; Four bridges have the reduced clearance OLE but one does have what is termed an 'extended neutral section'.

 

Neutral sections have also been used before where there was no other feasible way of obtaining clearance between the OLE and a structure, for example on the Cathcart Circle between Queens Park and Pollokshields East, and at Tams Brig near Newton Junction, Ayr.

These “extended neutral sections” are commonplace on today’s electrified railway. The long one on the MML goes all the way from Glendon to Sheffield....

[jamie92208]

These “extended neutral sections” are commonplace on today’s electrified railway. The long one on the MML goes all the way from Glendon to Sheffield....

Then you need stock that can run on 750DC for the bit from Woodburn to Parkgate before the next neutral section from Parkgate to either Moorthorpe. Donny or Colton Junction. You'd need a real good run up to bridge any of those gaps.

 

Jamie

[phil-b259]

Then you need stock that can run on 750DC for the bit from Woodburn to Parkgate before the next neutral section from Parkgate to either Moorthorpe. Donny or Colton Junction. You'd need a real good run up to bridge any of those gaps.

 

Jamie

 

Or just convert it to 25KV - something that has actually been designed into both the OLE and the new Tram-Train units.

 

Similarly the new Metro cars for Nexus will be capable of operating from 25KV with no modification if needed and I wouldn't mind betting that the same will be true of any new Trams ordered for Manchester or Nottingham in future too,

[eastwestdivide]

Then you need stock that can run on 750DC for the bit from Woodburn to Parkgate before the next neutral section from Parkgate to either Moorthorpe. Donny or Colton Junction. You'd need a real good run up to bridge any of those gaps.

 

Jamie

Being thoroughly pendantic (always a good way to improve a good joke!): 

1. Tinsley North Junction to Rotherham Parkgate Junction is where the 750DC overhead for the tram-trains coincides with the main line railway.

2. That stretch isn't strictly the Midland Main Line either, being ex-GC.

 

 

Yes that's a deliberate typo in the first line - it's not a hanging offence.

[geoff]

Here are a few snaps of the progress in Glendon cutting and through Kettering North Junction.

 

Geoff

 

IMG_5918 by Geoffrey Robinson, on Flickr

43048 leads the 1D22, 1034 St Pancras International to Nottingham service through Kettering North Junction two minutes early on Tuesday 31 July 2018 with the new masts and outriggers for the electrification to Corby in place along the Manton line tracks.

IMG_5914 by Geoffrey Robinson, on Flickr

43423 in revised livery and complete with buffers brings up the rear of 1D24, the 1005 St Pancras International to Nottingham service as it accelerates away from the Kettering stop through Glendon cutting.

IMG_5931 by Geoffrey Robinson, on Flickr

222017 rolls through Glendon South with 1P35, 1141 Corby to St Pancras International underneath the new masts and outriggers for the approaching electrification.

IMG_5936 by Geoffrey Robinson, on Flickr

73964 scoots along the main line past the new masts for the electrification of the line to Corby on its way home from Dr Brush at Loughborough. 0Z73 1024 Loughborough Brush to Tonbridge West Yard Gbrf. 10 minutes early.

IMG_5954 by Geoffrey Robinson, on Flickr

NMT HST powers through Kettering North junction with the late running  1Q52 09:00 BURTON OT WETMORE SIDINGS - 15:53 BURTON OT WETMORE SIDINGS .36 minutes late at 1519 on Thursday 2 August 2018.

[Dr Gerbil-Fritters]

I still can't believe that Corby will get electric trains to London and Leicester, Nottingham, Derby and Sheffield won't....

 

Corby... 

[griffgriff]

I still can't believe that Corby will get electric trains to London and Leicester, Nottingham, Derby and Sheffield won't....

 

Corby... 

With apologies to its residents but perhaps there are more people who wish to expedite their departure from Corby than from Derby, Nottingham and Sheffield

[DY444]

I still can't believe that Corby will get electric trains to London and Leicester, Nottingham, Derby and Sheffield won't....

 

Corby... 

 

I couldn't believe Royston got electric trains when Cambridge and Peterborough didn't.  Happened eventually though as will the remainder of the MML. 

 

Give the DfT time to go round the alternative energy, battery blah blah blah loop again and eventually they'll arrive back at the point they did 10 years ago after a similar exercise and realise that electrification is the best long term answer for major main line routes. 

 

Bi-modes *might* be the right answer for destinations off the main lines which can't justify electrification (eg Lincoln, Harrogate, Hull, maybe North Wales etc) but not as an alternative for electrification of the major routes.  I've got no idea how long it will take but the DfT will realise this eventually.  Bi-modes also give you the chance to extend the electrification in small, manageable sections which might prove advantageous in restoring confidence that it can be done on time and budget if you manage it properly.

Edited August 4, 2018 by DY444

[eastwestdivide]

...on its way home from Dr Brush at Loughborough...

Excellent!

 

I think they call the "outriggers" cantilevers, those in the pic being TTC = Twin Track Cantilever, allowing one vertical post+pile for two tracks.

Edited August 4, 2018 by eastwestdivide

[highpeakman]

Are you sure?  I didn't think that structures had had insulation placed on their undersides on Paisley Canal to reduce the flash over risk.  I thought it merely used reduced clearances (as indeed does Thameslink through the core) with consequent severe restrictions on the electric traction types that can be accommodated (again as per Thameslink core). 

 

Have top confess first that my memory is uncertain these days but didn't one of the original 25kV OLE systems (GE from Liverpool St.?) initially use dual voltage? 25kV for most of the route but a lower voltage AC (1.5kV?) for some sections where the clearances were poor? Units were obviously auto dual voltage. It was later changed to just 25kV everywhere - presumably clearances were improved.

 

So, if my memory is correct (and it probably isn't) would this be a solution? I am positive many people on here can provide good reasons why it would not be and that also my memory is wrong.

[jamie92208]

Have top confess first that my memory is uncertain these days but didn't one of the original 25kV OLE systems (GE from Liverpool St.?) initially use dual voltage? 25kV for most of the route but a lower voltage AC (1.5kV?) for some sections where the clearances were poor? Units were obviously auto dual voltage. It was later changed to just 25kV everywhere - presumably clearances were improved.

 

So, if my memory is correct (and it probably isn't) would this be a solution? I am positive many people on here can provide good reasons why it would not be and that also my memory is wrong.

As far as I can remember both the Glasgow Blue Trains and the Liverpool St lines had a 6.25Kv/35Kv system due to clearance problems. I think it was all converted to straight 25Kv after the various experiments that lead to the clearances that we've used for many years that also had to cope with steam traction. I think that the changeover equipment had reliability problems as well.

 

 

Jamie

[Zomboid]

It was 6.25kV. There's no technical reason why it couldn't be used in other applications, but it would increase the complexity of the trains if they had another voltage to switch around and between, and lower voltages require a lot more substation infrastructure.

 

For something like the bridge at Leicester, a neutral section would be undesirable but not beyond possible. If trains were fitted with on board energy storage (I'm thinking like 1 miles worth of battery capacity) a lot of the really awkward bits could be dealt with in such a fashion - normally coast through, but able to self rescue to a live bit if they run out of momentum whilst off the juice. It would create timetabling fun though, as electric trains wouldn't be going very fast or accelerating through the affected areas.

[jamie92208]

It was 6.25kV. There's no technical reason why it couldn't be used in other applications, but it would increase the complexity of the trains if they had another voltage to switch around and between, and lower voltages require a lot more substation infrastructure.

 

For something like the bridge at Leicester, a neutral section would be undesirable but not beyond possible. If trains were fitted with on board energy storage (I'm thinking like 1 miles worth of battery capacity) a lot of the really awkward bits could be dealt with in such a fashion - normally coast through, but able to self rescue to a live bit if they run out of momentum whilst off the juice. It would create timetabling fun though, as electric trains wouldn't be going very fast or accelerating through the affected areas.

Having seen a lot of the new trunking for 25Kv feeds, such as near Hitchin, perhaps some form of solid bar actually fixed to the roof of the tunnel wold be possible. The trunking only looks to be about 5" square so with no need for insulation underneath you could probably make a composite girder about 6" deep that would work a treat.

 

Better get off to the patent office.

 

Jamie

[Edwin_m]

Have top confess first that my memory is uncertain these days but didn't one of the original 25kV OLE systems (GE from Liverpool St.?) initially use dual voltage? 25kV for most of the route but a lower voltage AC (1.5kV?) for some sections where the clearances were poor? Units were obviously auto dual voltage. It was later changed to just 25kV everywhere - presumably clearances were improved.

 

So, if my memory is correct (and it probably isn't) would this be a solution? I am positive many people on here can provide good reasons why it would not be and that also my memory is wrong.

The first sections of the GE line were electrified at 1500V but soon after were converted to AC electrification when BR standardised on this system except for extensions of third rail areas.  Manchester to Hadfield was similarly converted much later, after rest of the Woodhead line closed. 

 

The converted GE and some other AC routes used a voltage of 6.25kV on the sections where cleraances were tight.  This is a quarter of the standard 25kV so the trains could have some relatively simple equipment to re-configure the transformer depending on what voltage was detected, so that the traction system connected to the transformer secondary got the same voltage all the time.  I think the changeover system was partly responsible for several rather spectacular explosions of EMUs in Glasgow when it didn't work as advertised. 

 

The dual voltage system was eliminated when BR worked out that that 25kV could be used with much tighter clearances than previously assumed, so there was little if any need to increase clearance on the 6.25kV sections before converting them to 25kV.  Some of them lasted into the 1980s but were used by EMUs only, and I believe classes 81-85 were equipped with the dual voltage system but class 86 and 87 weren't.   Hence, even if any current trains could use it, adopting 6;.25kV wouldn't allow any reduction of clearances. 

Edited August 4, 2018 by Edwin_m

[jim.snowdon]

Just as the clearances required for 25kV were found capable of being reduced, rendering the need for 6.25kV unnecessary, the clearances required for the lower voltage would also have been found capable of reduction. There would not, however, have been any purpose to investigating that any further once everything could be standardised at 25kV.

 

Jim

[Edwin_m]

Just as the clearances required for 25kV were found capable of being reduced, rendering the need for 6.25kV unnecessary, the clearances required for the lower voltage would also have been found capable of reduction. There would not, however, have been any purpose to investigating that any further once everything could be standardised at 25kV.

 

Jim

Wasn't 6.25kV chosen because its clearances were no worse than those for 1500V?  And clearances at 1500V are largely down to mechanical issues and tolerances, as the arcing distance is negligible. 

[highpeakman]

As far as I can remember both the Glasgow Blue Trains and the Liverpool St lines had a 6.25Kv/35Kv system due to clearance problems. I think it was all converted to straight 25Kv after the various experiments that lead to the clearances that we've used for many years that also had to cope with steam traction. I think that the changeover equipment had reliability problems as well.

 

 

Jamie

 

Thanks to you, and the other people who responded, for confirming that. Makes me feel a bit better that my memory is, at least, partially correct. I should have remembered it was 6.25kV though.

 

I understand the arguments for getting rid of the 6.25kV in the earlier system but still wonder if there would be a case for considering it on a modern line where modifying clearances can be very expensive and disruptive. Developments in control systems during the last 50 years should bring much improved reliability so that should be less of a problem. I would not have thought that a modern changeover system would add massive amounts in size and cost to the control systems? There will be some gain in clearance by using 6.25kV compared to 25kV that might be enough to make a difference.

 

However, of course, I do understand that it would be much more sensible to make the infrastructure work on a single voltage and not have to modify all of the trains.

Edited August 5, 2018 by highpeakman

[jim.snowdon]

Wasn't 6.25kV chosen because its clearances were no worse than those for 1500V?  And clearances at 1500V are largely down to mechanical issues and tolerances, as the arcing distance is negligible.

 

It also has the considerable convenience of being 1/4th of the normal 25kV system voltage, which made the series-parallel switching of the sections of the transformer primary winding. The down side was that all the switching was on the high voltage side.

 

Clearances are still a problem, not helped by the rules under the Interoperability directive and the UK's lack of a coherent response to the differences in its railways relative to the rest of Europe. A lot of useful work has been done, though, to demonstrate that even tighter clearances are possible with careful engineering.

 

Jim

[RANGERS]

Interesting that EMT were reporting delays this evening to services to and from LStP as a result of power supply issues. Presumably its screwed up GTR services and had a knock on effect but a strange way to report it.