Modern single track mainlines

[hexagon789]

45 minutes ago, Compound2632 said:

 

But Perth-Stanley was of course part of the Caledonian main line to Aberdeen - route of the West Coast Postal, the Royal Train route, and arguably a section of the mainest of main lines in the country.

And other than the severe curve through Forfar, pretty straight as well. There are a number of logs of A4s from the 1962-66 ScR Swansong of the class show speeds into the 80s even as high as 90-odd attained sometimes. I think that speaks as to the quality of the line.

[keefer]

IIRC at that time, the Highland line was the 'branch'!

[H2O]

Not quite single / double as per the OP request but on Filton bank (going out of Bristol) the capacity was halved in the 80's and recently doubled back to 4 tracks.

 

I used to think that any reduction such as singling was a great loss but 40 or 50 years saving on maintenance from some of the schemes listed here may have let other lines survive?

Edited April 3, 2022 by H2O

[The Stationmaster]

3 hours ago, H2O said:

Not quite single / double as per the OP request but on Filton bank (going out of Bristol) the capacity was halved in the 80's and recently doubled back to 4 tracks.

 

I used to think that any reduction such as singling was a great loss but 40 or 50 years saving on maintenance from some of the schemes listed here may have let other lines survive?

I suspect that many - if not all of the WR singling schemes - have paid for themselves many times over as they will have saved millions in renewal costs let alone any continuing maintenance costs.  The 'only' with them was that they obviously reduced line capacity bi ut in many cases the capacity that went was no longer and has not been needed since.  I think the two with the greatest retrograde effect were Swindon - Kemble - which at times played h*ll with punctuality, and was sorely tested by the Swindon - Longbridge 'just-in-time' car body pressings trains which had severe penalty clauses in their contracts, although what led to the return to double track came long after they had ceased to run.  Burngullow - Probus was the other one that became an increasing embarrassment at times of out-of-course running.  However both needed the financial change resulting from the creation of Network Rail for the financing to be made available to do anything about them.

 

Dequadrification (horrible word) of Filton Bank saved a massive amount of money through avoided major bridge repairs/renewals and in the traffic situation of the time was not a significant operational problem.  Again what led to some reinstatement, and more importantly the money to do, came from changing traffic circumstances in the Bristol area plus Network Rail actually being able to create financing for such enhancements in a way that BR never could and Railtrack never wanted to.

[Mike_Walker]

The single track between Swindon and Kemble continues to cause grief for those of us trying to demonstrate Swindon Panel to the public at Didcot!  

[Hal Nail]

Does the old New North Mainline count? Whilst the link at Old Oak has been severed, the singled stretch alongside the Central line through Northolt and Greenford is still in use and I think some freight may use the section beyond past Hangar Lane (does anyone know?)

 

When I moved away a year ago there was still a daily parliamentary 'ghost' train running over the section from South Ruislip to the Greenford loop.

Edited April 6, 2022 by Hal Nail

[eastglosmog]

On 03/04/2022 at 12:01, The Stationmaster said:

I suspect that many - if not all of the WR singling schemes - have paid for themselves many times over as they will have saved millions in renewal costs let alone any continuing maintenance costs.  The 'only' with them was that they obviously reduced line capacity bi ut in many cases the capacity that went was no longer and has not been needed since.  I think the two with the greatest retrograde effect were Swindon - Kemble - which at times played h*ll with punctuality, and was sorely tested by the Swindon - Longbridge 'just-in-time' car body pressings trains which had severe penalty clauses in their contracts, although what led to the return to double track came long after they had ceased to run.  Burngullow - Probus was the other one that became an increasing embarrassment at times of out-of-course running.  However both needed the financial change resulting from the creation of Network Rail for the financing to be made available to do anything about them.

 

.....

One of the public reasons given for singling long stretches of the Cotswold line was easing of curves with consequent reduction in maintenance costs.  This included the sharpest curve on the line at Aston Magna (caused by a landslip during construction).  With the redoubling, the Aston Magna curve is back to its former sharpness so presumably maintenance costs have gone back up.  The curvy section through the Evenlode gorge from Charlbury to Yarnton remains single.  I suspect this is due to being able to keep the track in the center of the deep cuttings on this stretch, reducing the need for maintenance on the cutting sides, rather than easing the curves.  The cuttings are showing their age.

[The Stationmaster]

2 hours ago, eastglosmog said:

One of the public reasons given for singling long stretches of the Cotswold line was easing of curves with consequent reduction in maintenance costs.  This included the sharpest curve on the line at Aston Magna (caused by a landslip during construction).  With the redoubling, the Aston Magna curve is back to its former sharpness so presumably maintenance costs have gone back up.  The curvy section through the Evenlode gorge from Charlbury to Yarnton remains single.  I suspect this is due to being able to keep the track in the center of the deep cuttings on this stretch, reducing the need for maintenance on the cutting sides, rather than easing the curves.  The cuttings are showing their age.

I think all sorts of 'reasons' were offered in public for various rationalisation schemes but particularly for the singlings.  However in reality each scheme was assessed strictly on its financial impact with some (usually quite limited) input regarding any potential operational impacts.  But money - mainly in avoided relaying costs - was at the heart of all the schemes especially if a route was otherwise likely to become at risk of closure due to the need for extensive track renewals.  And on many of the secondary routes deferred relaying items, in some cases eventually accompanied by temporary restrictions of speed, tended to increase over time because WR policy was to concentrate perway funds on providing the best possible attention to, and renewal of track, on the principal main lines 

 

I'm not sure about the late 1960s schemes but by the mid 1970s the singling schemes were assessed on a discounted cash flow basis over 25 years with cost of the singling work, including signal alterations etc, set against the value of any recovered reusable material plus avoided relaying costs over the life of the project.  In some cases singling was 'encouraged' (or even due to in the case of the Cornish viaducts) for other infrastructure reasons such as bridgeworks or, much less commonly the state of embankments and cuttings.   But the costing always used avoided costs over the project as part of teh financial assessment.

[Mike_Walker]

There are aspirations to complete the redoubling of the North Cotswold line at both ends but whether this will be achieved in a post-pandemic world remains to be seen.

 

The Aston Magna curve is now subject to a 70mph PSR which is only a slight reduction on the prevailing 75mph on the Moreton-in-Marsh to Evesham section.

 

[Morello Cherry]

I think that the some of the reasons why Charlbury - Wolvecote is still single track and wasn't redoubled, much to the annoyance of anyone who has been sat on a train at either Charlbury or Wolvecote waiting for one to come the other way, are because of the cost of the doubling the junction at Wolvecote. Also either Finstock or Coombe (I forget which) when the line was singled the platform was moved from its old location and into the formation so if that section were redoubled then the halt would need to be rebuilt which would be a very high cost for number of passengers who use the one train a day each way from the station.

 

Edited April 6, 2022 by Morello Cherry

[russ p]

There was a plan in the early 80s when the GE mainline electrification north of Ipswich was been planned to single the line north of of Haughley to Norwich with a loop at Diss.  Good job that that didn't happen 

[The Stationmaster]

28 minutes ago, Mike_Walker said:

There are aspirations to complete the redoubling of the North Cotswold line at both ends but whether this will be achieved in a post-pandemic world remains to be seen.

 

The Aston Magna curve is now subject to a 70mph PSR which is only a slight reduction on the prevailing 75mph on the Moreton-in-Marsh to Evesham section.

 

It was 50mph in double line days - including back in the days before the line speed between Moreton and Evesham was reduced from 90mph to 75mph.

[Nick C]

There's also the Ashford-Hastings line, if that counts as a main line - not only has it been singled, but like the Uckfield line mentioned above, it's one of only a handful of non-electrified sections in the South-East.

[luckymucklebackit]

Parts of the Airdrie to Bathgate line had an interesting history, originally opened a single track, it was then doubled, then singled in the 1970s, closed and lifted in the 1980s then Airdrie to Drumgelloch was reopened as single, then reopened completely as double in 2010

 

Jim

[melmerby]

On 01/04/2022 at 09:46, hexagon789 said:

The Highland Main Line between Perth and Inverness has never been fully double track, but what had been doubled in the 1900s was singled in the 1960s only to be redoubled in 1978. Originally double Perth-Stanley; Blair Atholl-Dalwhinnie and Culloden-Inverness, BA to Dalwhinnie and Culloden to Tomatin were singled and a number of passing loops removed. Rising tourist traffic and the oil boom saw Blair-Dalwhinnie redoubled, 3 passing loops reinstated and plans to single Tomatin-Inverness shelved.

 

 

Shouldn't that read Tomatin to Inverness?

[eastglosmog]

8 hours ago, Morello Cherry said:

I think that the some of the reasons why Charlbury - Wolvecote is still single track and wasn't redoubled, much to the annoyance of anyone who has been sat on a train at either Charlbury or Wolvecote waiting for one to come the other way, are because of the cost of the doubling the junction at Wolvecote. Also either Finstock or Coombe (I forget which) when the line was singled the platform was moved from its old location and into the formation so if that section were redoubled then the halt would need to be rebuilt which would be a very high cost for number of passengers who use the one train a day each way from the station.

 

I am not convinced that those were the main reasons - after all, the line could have been redoubled another 6 miles at least as far as Long Hanborough station, or even a few more miles to Yarnton, and still left the Wolvercote Junction single.  Would have shortened the  time spent traversing the single line stretch from 12 mins or so to about 5. 

As for the Finstock, it would certainly seem a lot of effort for 1 train each way each weekday, but Ascot was totally rebuilt and has the same service, so not an overriding factor.

9 hours ago, Mike_Walker said:

There are aspirations to complete the redoubling of the North Cotswold line at both ends but whether this will be achieved in a post-pandemic world remains to be seen.

 

The Aston Magna curve is now subject to a 70mph PSR which is only a slight reduction on the prevailing 75mph on the Moreton-in-Marsh to Evesham section.

 

The superelevation around the Aston Magna curve that allows 70mph is impressive.  One of my favorite train watching locations.  Interestingly, the single line stretch from Charlbury to Yarnton is 100mph line speed (the speed limit board is visible from the Cornbury bridge).

[hexagon789]

4 hours ago, melmerby said:

Shouldn't that read Tomatin to Inverness?

In fact not even that, Daviot was the southernmost extent of double line, Culloden is where it was cut back to. I'll go back and edit my post though, thanks for spotting my error there.

[melmerby]

7 hours ago, hexagon789 said:

In fact not even that, Daviot was the southernmost extent of double line, Culloden is where it was cut back to. I'll go back and edit my post though, thanks for spotting my error there.

 

I thought it went somewhere south of Culloden as you can still see the double track formation in many places, whilst on the train.

I tried using the old 25" maps to see where but got as far as Daviot before they ran out.

In fact looking at the 6" maps it runs out a few yards past the map border!

https://maps.nls.uk/geo/explore/#zoom=17&lat=57.42933&lon=-4.10270&layers=6&b=1

[hexagon789]

17 minutes ago, melmerby said:

 

I thought it went somewhere south of Culloden as you can still see the double track formation in many places, whilst on the train.

I tried using the old 25" maps to see where but got as far as Daviot before they ran out.

In fact looking at the 6" maps it runs out a few yards past the map border!

https://maps.nls.uk/geo/explore/#zoom=17&lat=57.42933&lon=-4.10270&layers=6&b=1

You can certainly see the previous double formation around the Culloden area, I think that's the most visibly obvious section.

[Morello Cherry]

12 hours ago, eastglosmog said:

I am not convinced that those were the main reasons - after all, the line could have been redoubled another 6 miles at least as far as Long Hanborough station, or even a few more miles to Yarnton, and still left the Wolvercote Junction single.  Would have shortened the  time spent traversing the single line stretch from 12 mins or so to about 5. 

As for the Finstock, it would certainly seem a lot of effort for 1 train each way each weekday, but Ascot was totally rebuilt and has the same service, so not an overriding factor.

The superelevation around the Aston Magna curve that allows 70mph is impressive.  One of my favorite train watching locations.  Interestingly, the single line stretch from Charlbury to Yarnton is 100mph line speed (the speed limit board is visible from the Cornbury bridge).

 

Perhaps but I think it is the area of the line with high redoubling costs and low returns.

 

You would need to rebuild three stations - LH, Coombe and Finstock. All would need platforms and ways of accessing the platforms (I think access to Finstock each way used to be via steps on the road bridge). Coombe is pretty much a platform in a field. Only LH warrants it in terms of passenger use, and pretty much nothing has been done to improve the facilities there other than building a bigger carpark.

 

Coombe pre-covid was at c2700 passengers a year and Finstock at c1500.

 

You'd have to completely remodel and resignal Wolvecote as well, the present set up allows for an hourly service, while increased flexibility would be nice and the long gaps can be a pain if you miss a train, I am not sure there is the rolling stock available to run a more intensive service. (Hello 165 substitutions).

 

Should have been redoubled but I can understand why it wasn't.

 

As a footnote the proposed costs in 2016 for redoubling this section were £275 million...

Edited April 7, 2022 by Morello Cherry

[45655]

On 06/04/2022 at 10:59, The Stationmaster said:

I'm not sure about the late 1960s schemes but by the mid 1970s the singling schemes were assessed on a discounted cash flow basis over 25 years with cost of the singling work, including signal alterations etc, set against the value of any recovered reusable material plus avoided relaying costs over the life of the project. 

I wonder how that panned out with the 1980s Farnham-Alton singling. That must have been when they discovered that it's one thing to operate third rail electrification over a single line on a little tramway like Wimbledon-West Croydon and another altogether if you have 12 car trains running up and down at 70mph during the peaks.

 

As  understand it the the redundant second line had to be left in situ for some years to provide adequate traction current capacity and could only be lifted after a new HV cable was run down and transformers put in at the former TP huts to convert them to substations.  I think some of the redundant track was eventually donated to the Isle of Wight Steam Railway for their Smallbrook extension.

 

The sheer amount of current flowing around used to play merry hell with the signalling.  It was not uncommon for a 12 car train starting away from the passing loop at Bentley to put the signal back to red in front of the other train.

 

The more recent power supply upgrade for the Desiro stock had its moments, too, particularly at Alton (which is an electrical dead end).  Network Rail was obliged to bond the first section of the Mid-Hants line west of the station for traction current return and provide a new HF track circuit, as a Desiro starting away would put their signals back to red.

 

Given that (pre-Covid) the single line was used pretty much to capacity with a half hourly service all day, one has to wonder with hindsight whether this was British Rail's brightest move.

 

Keith (a sometime Alton commuter).

[Nick C]

52 minutes ago, 45655 said:

Given that (pre-Covid) the single line was used pretty much to capacity with a half hourly service all day, one has to wonder with hindsight whether this was British Rail's brightest move.

It is again now - at least on Saturdays, there's a half-hourly service all day.

[Ncarter2]

On 01/04/2022 at 20:57, Artless Bodger said:

Wool (?) to Dorchester South? Was this singled when electrified as the supply is inadequate for more than 1 train in the section?

It’s a bit further down the line, Moreton to Dorchester. Done as part of the 1980’s electrification as I understand to save money, also the timetable was such that only one train was to be in section, so the line could be singled. The supply from Poole to Weymouth was done on the cheap, single unit operation is the norm. Even now, down Weymouth there can be issues. 

[ChrisN]

Am I right in remembering the line north of Oxford to Birmingham is singled near, around, through Banbury.  I was quite surprised when I travelled on it a few years ago and saw it was single.  (2017/2018?)

[melmerby]

23 minutes ago, ChrisN said:

Am I right in remembering the line north of Oxford to Birmingham is singled near, around, through Banbury.  I was quite surprised when I travelled on it a few years ago and saw it was single.  (2017/2018?)

If it was it isn't now it's double track all the way

 

IIRC any single track was re-doubled during "Evergreen 1" about 20 years ago.

Edited April 8, 2022 by melmerby