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Carstairs (electrification of)


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Hello all

 

A bizarre one, I know. I am trying to work out the precise location of the termination of the catenary heading away from Carstairs, before the line to Edinburgh suffered electrification.

 

I seem to recall that it was on a left hand curve and the terminating gantry was offset to the right, rather than above the running line. It was only a short distance away from the junction. I don't recall whether it was before going over the first bridge (Lampits Road), though it was about this point where the Brush 4 would open up- after the curve over Lampits Road, the line is straight and presumably has a higher speed rating.

 

If anyone knows of any old cab videos on youtube, or indeed if any regular passengers/ rail staff know the exact location, I would be appreciative... Even whether it was before or after the bridge would be useful.

 

Many thanks.

 

 

 

Edited by Derekstuart
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  • 3 weeks later...

Let me start by saying I don't know for sure but my (perhaps faulty) recollection was that the ole only went a short distance round the curves from the WCML. 

 

This is by no means infallible but often the start points of extensions to electrification can be established from the positions of neutral sections especially if they are odd.  And the positioning of the neutral sections at Carstairs are a bit odd even by the "logic" which applies to their positioning in general (which is a whole fun topic all of its own).   There's one on the north to east curve, another on the WCML just south of South Jn and a third on the south to east curve.  The latter two being very close together (indeed if they are two neutral sections closer together anywhere in the UK then I'd be interested to know where).  The neutral sections on the two curves are each towards the WCML end.  

 

The question therefore is this.  If the 1970s ole extended all the way round to the East Junction or even beyond then why are there neutral sections on the curves?  Is it credible that the original ole design had two neutral sections literally a few hundred yards apart either side of the South Jn?  Why in the original 1970s scheme would you go to the cost and trouble of putting two neutral sections on what amounted to extended run offs?  If the original ole extended beyond East Jn without the neutral sections on the curves then why would they have been retro fitted as part of the Edinburgh extension?  Surely cheaper and easier to put a single one beyond the East Jn?  Even by the weird logic that seems to apply to neutral sections it makes no sense at.  What does make sense is adding neutral sections at the end of the existing run offs and starting the extension from there.  It seems to me therefore that there is a decent chance that the neutral sections on the curves denote the limit of the original ole and the start point of the extension towards Edinburgh.

 

Now I withdraw and wait for the inevitable posting of evidence which proves my theory to be total nonsense. 

Edited by DY444
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Are they neutral sections or insulated overlaps?  Normal practice at the time was to have "overrun protection", the idea being that should an Electric train get wrongly routed, the driver had a chance to stop and back up, as well as ensuring the pantograph did not wreck anything by falling off the wire in the middle of a junction.  The length of overrun protection required was based upon line speed, so the faster a train might take the diverging route, the longer the overrun protection provided. 

 

Where the wire ended was wired as half an overlap, with suitably sized structures such that should the diverging route be electrified then conversion to a full overlap was possible just by adding Small Part Steelwork (SPS) without having to alter any of the existing wiring or install new structures.

 

So although it is not a hard and fast rule, it was probably wired as far as the first wire anchor or balance weights on the current configuration.

 

Having said that, electrified diverging routes were often fed from a different substation, which could mean neutral sections could be placed in odd positions depending on what the feeding arrangements were, as options may be required for feeding the junction from either substation either for maintenance purposes or when a substation is switched out and you are back feeding from the next one.

Edited by Titan
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I think this photo may show the final post where the electrification stopped, the one immediately in front of the 47 (far left background).

Could well be wrong though.

SC 36 47487 180488

Photo by Steven Clements on Flickr

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In all my visits to Carstairs I would occasionally venture down to Strawfrank but never as far out as the East Junction.  Some photographs that would give clues though, this winter view Carstairs Winter is looking towards Carstairs East and the Road Bridge connecting the old and new parts of the hospotal can be seen in the distance, it looks as though the wires stop just on the other side of the bridge, it certainly went further than the post mentioned by Flood, as not only was the main line wired, the through siding was also wired right round to Carstairs East Junction.

 

Corrected bridge description

 

Jim

Edited by luckymucklebackit
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2 hours ago, Titan said:

Are they neutral sections or insulated overlaps? 

WCML neutrals just outside the TSC, and Midcalder line neutrals on the  triangle. It is a bit odd, but the WCML ones will be in the original location, and the ones on the curves obviously added later, and that's what the overall design looks like.

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Having travelled quite frequently between Edinburgh and Carstairs over the past few years (since relatives moved to near there) I can confirm the thing on the roof gives a big bang after you've gone past the East Junction!  And going in the opposite direction, with the speed limit round the curve from the station being so low, it always seems to me that there is a big risk of the unit becoming 'gapped' before it gets back under the juice again.

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14 hours ago, brushman47544 said:

I thought all sides of the triangle were electrified. This photo appears to show the curve to Edinburgh was electrified http://www.scot-rail.co.uk/photo/scaled/16741/

 

Most non-electrified diverging lines have wiring for a short distance.  The curves at Carstairs were no exception.  The question is how far the original 1970s wiring at Carstairs went round the curves before the Edinburgh extension.  That picture doesn't tell us one way or the other.  The positioning of the neutral sections on the curves today suggests the original electrification only went part way around each of the curves.

Edited by DY444
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Watching this video, there is a change of style of masts at around 51:10 (Lampits Rd bridge nr the Hospital) to the ECML double track style with the short support link between the support tube and the diagonal, and might explain why the wire sections change so soon after the crossover. 

 

Any thoughts?

 

 

Edited by 298
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On 11/12/2020 at 16:34, 31A said:

Having travelled quite frequently between Edinburgh and Carstairs over the past few years (since relatives moved to near there) I can confirm the thing on the roof gives a big bang after you've gone past the East Junction!  And going in the opposite direction, with the speed limit round the curve from the station being so low, it always seems to me that there is a big risk of the unit becoming 'gapped' before it gets back under the juice again.

 

The positioning of OLE Neutral sections is an interesting, if somewhat specialised, subject ! I cannot recall any trains getting stranded in any of those at Carstairs, but we have a couple in Scotland where it does occur; On the Up ECML just after Longniddry station, and on the Up Argyle Line just after Rutherglen station. In both cases trains starting from the station stop are vulnerable, especially at times of low rail adhesion, and the NS at Rutherglen being on a sharp curve does not help either. 

 

I am disappointed (in myself) that despite having worked in Glasgow Control 1984-87 and 1989-2016, plus having been the Anglo-Scot Controller for some of those years, that I cannot now recall the NS arrangements at Carstairs, or even whether the whole triangle was wired in 1974; Passenger trains of course could simply reverse (or divide) and at the same time re-engine in the station, but this would have been more awkward for freights. Therefore I would have thought that all three sides were indeed wired; I am still attempting to confirm this. 

 

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On 13/12/2020 at 13:00, caradoc said:

 

The positioning of OLE Neutral sections is an interesting, if somewhat specialised, subject ! I cannot recall any trains getting stranded in any of those at Carstairs, but we have a couple in Scotland where it does occur; On the Up ECML just after Longniddry station, and on the Up Argyle Line just after Rutherglen station. In both cases trains starting from the station stop are vulnerable, especially at times of low rail adhesion, and the NS at Rutherglen being on a sharp curve does not help either.

My knowledge of them is purely down to simulations of questionable accuracy rather than the real world but on that some of them (on the only route I've got where they've been implemented) did seem to be placed for maximum inconvenience. One shortly after leaving Penrith springs to mind. Think there was also one nicely placed at the start of the northbound climb up to Shap that I have a vague recollection has been moved.

Edited by Reorte
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Based on a discussion with one of the  electrification team in 1990 (I was going through long section surveys) I think the NE to south curve was inclined in the wiring plans as up to then there was no possibility of doing a loco change on that curve whereas an electric loco had to be able to use the NE- NW curve post 1974 due to the location of the holding sidings. The majority of that discussion however was related to the most god forsaken locations to get to to do surveys. While Carstairs is in the middle of nowhere when travelling there by car we came to the conclusion that South Lynn Jct was the worst - although under the A47 the nearest foot access was nearly a mile away and during the walk you had to endure (for some of the year) the WMD which was the sugar beat factory.

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3 hours ago, Reorte said:

My knowledge of them is purely down to simulations of questionable accuracy rather than the real world but on that some of them (on the only route I've got where they've been implemented) did seem to be placed for maximum inconvenience.

 

The location of the Rutherglen Neutral Sections is understandable, given that the route was electrified (in fact, re-opened) some years after the main line was electrified, and it is a logical separation point. Longniddry, on the other hand, less so.....

 

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12 minutes ago, caradoc said:

 

The location of the Rutherglen Neutral Sections ...

 


Sorry to lower the tone of this topic - which I have found interesting - but I’m re-reading the “Hitchhiker’s Guide” books and that phrase seemed familiar.

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Aside from the carrier wire type used on the GWML, the neutral bit of a neutral section is only a couple of metres long. The wires either side are live, so actually getting stuck with the pan on the dead bit is pretty difficult to do.

 

Stalling between APC magnets is a different matter - somewhere like Longniddry the line speed is quite high, so they have to be quite widely spaced, and slower traffic can struggle. At Carstairs triangle the line speed is really low, so there's no issues with APC magnet position for fast trains catching out slower ones. If a train were to get stuck between magnets but on live OLE then in theory they could put the breaker back in and motor away, but they'd need to know which side of the actual neutral section the pan is to determine whether forward or backwards is the better idea. Probably safer and simpler to summon assistance given how rare an event it is.

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5 hours ago, Zomboid said:

Aside from the carrier wire type used on the GWML, the neutral bit of a neutral section is only a couple of metres long. The wires either side are live, so actually getting stuck with the pan on the dead bit is pretty difficult to do.

 

Stalling between APC magnets is a different matter - somewhere like Longniddry the line speed is quite high, so they have to be quite widely spaced, and slower traffic can struggle. At Carstairs triangle the line speed is really low, so there's no issues with APC magnet position for fast trains catching out slower ones. If a train were to get stuck between magnets but on live OLE then in theory they could put the breaker back in and motor away, but they'd need to know which side of the actual neutral section the pan is to determine whether forward or backwards is the better idea. Probably safer and simpler to summon assistance given how rare an event it is.

 

Don't know about now but back in the day the driving manuals for AC traction used to contain specific instructions on how to extricate yourself from being stuck between APC magnets.  As you suggest it did require you to figure out the position of the pan relative to the dead bit before deciding what course of action to follow. 

Edited by DY444
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  • 3 weeks later...

Not sure if this will help or not but i came across this photo on FlickR today.

370001

 

Anybody know why the APT will have gone onto the triangle instead of using a loop?

 

Would a possibilty have been that they wanted to reverse the direction? If so that would suggest the whole triangle was electrified and far enough toward Edinburgh for the APT to reverse up it?

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The APT is returning to Glasgow and about to switch onto the down line. The driver would have to have changed ends - putting it on the curve would cause less problems than doing it  on the up main, that's assuming up main (wrong line) to down main was signalled).

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