Single Track Pinch Points

[LE Greys]

Thinking about single-track bridges, the Royal Albert Bridge at Saltash is a bit of a problem. It was originally going to be double-track, but cuts (yes, cuts) meant that it had to be single. Must cause quite a bottleneck, and I cannot think of any way to avoid it other than tunnelling under the Tamar. Building a new bridge alongside or replacing the old one would probably not be allowed, although they did build the road bridge next to it.

 

[MidnightFlyer]

With on average 1tph in each direction, is the Royal Albert Bridge really that bad?

 

[Xenophon PCDGS]

Could one line work bi-directional for westbound Metro and all freight and the other line work one-directional for eastbound Metro only?

I saw this posting that mentioned the Metro and this brought to mind the current works to change the Oldham loop heavy rail line to the Manchester Metrolink system. Many years ago, the line section from Shaw to Rochdale was singled, but the new conversion plans will reinstate double track running over that section. However, the Wellington Bridge that carries the line over the river Roche has been deemed as strong enough to only carry one set of tracks in its present condition, so to save money on carrying out the required works, which would give unhindered double track running, a new pinch-point has occurred in the area of this bridge.

 

[MrC]

• Wool - Dorchester (the bit of the Weymouth line singled when it was electrified, the usual completely daft dessision)

While this would be handy, and agree it should never have been done, I'd hardly say it was a priority compared with some of the other lines mentioned in this thread. It handles 4 trains an hour OK at the moment with the occasional sand train etc with no problems and pathing for occasional specials seems to be available. After all it only takes about 6-7 mins to get from Moreton to Dorch, less if not stopping at Moreton.

 

[lancastrian]

As part of a study into better Central Belt-Aberdeen trains, they suggested re-routeing the railway via a new bridge to the west, as the SLW section is a real pain for faster / more trains.





They are looking a two new loops (I forget the locations; I think one a way north of Dunkeld and one near Blair Atholl / Newtonmore), and they are running extra services over the line from December, I don't quite think it makes it hourly though...



Could be solved with crossing loops at Entwistle, St Annes and Burnley Central respectively

You are right they could be, BUT if that was allo that was done, then a job that could be done today for say 20 million, would cost at least 5 to 10 more in only a few years. "Saving money" today, often costs way more when it finally dawns upon our supposed elected representatives (of any party) that it should have been done properly at first.

 

[DaveNewcastle]

With on average 1tph in each direction, is the Royal Albert Bridge really that bad?

Are you sure about that?
I'm familiar with more like 3 times that during weekday daytimes - are you including freight and the odd departmentals and ECS in there and averaging over several consecutive daylight hours? Sure its dead at night time, but capacity isn't judged on averages but on ability to deliver its demand (whenever that demand occurs).

(Or maybe I only cross the road bridge dead on that hourly rail crossing by coincidence)

 

[apk55]

My local station Navigation road is an interesting bit of single track, with two separate single track railways (Metrolink & mid Cheshire).
Metrolink runs a 6 min service over the section of single track which is only about 500m or about 1km between protecting signals.

This was done to avoid joint running with metrolink and railtrack.

The mid Cheshire line also has 2 other sections of single track, Moldsworth to Mickle Trafford Junction near Chester and between Northenden and Stockport. Both of these sections were double track although some bridges near Stockport have been replaced by single track structures.

 

[Tracky]

Not a single track but a clear bottleneck or pinch point is Castlefield Junction. Network Rail have identified this and i am led to believe may, in the short term, be looking to run more services into Victoria.

I do wonder if the line could be re-instated between Skelton Junction and Glazebrook Junction for use by EMT (and maybe TPE) trains that currently run through 13/14 and Oxford Rd. The added bonus operationally being that a late running EMT service could be turned round at Stockport rather than Picc to reduce a delay.

 

[apk55]

I do wonder if the line could be re-instated between Skelton Junction and Glazebrook Junction for use by EMT (and maybe TPE) trains that currently run through 13/14 and Oxford Rd. The added bonus operationally being that a late running EMT service could be turned round at Stockport rather than Picc to reduce a delay.

The line from Skelton Junction and Glazebrook Junction looks possible to re instate without much difficulty as the root is intact, although the bridge over the A56 is only single track. (In contract the Lymn line has been well built over at Broadheath so re reinstatement would be much more difficult)

 

[Tracky]

The line from Skelton Junction and Glazebrook Junction looks possible to re instate without much difficulty as the root is intact, although the bridge over the A56 is only single track. (In contract the Lymn line has been well built over at Broadheath so re reinstatement would be much more difficult)

Looking at OS and Birdseye views I would say the A56 is a "simple" structure to deal with and the bridge over the Ship Canal is the problem.

A quote from wikipedia reads...

Following the withdrawal of passenger services in 1964, the line became freight only and when expensive repairs to the viaduct were needed the early 1980s British Rail closed the viaduct and the preceding line towards Glazebrook.

It is now blocked with containers on each end due to youths using it for anti social behaviour and to stop people walking across it as the deck of the viaduct is in a very bad state with major corrosion setting in on the soffits and trough decking of the major steel span of the viaduct.

 

[Xenophon PCDGS]

Looking at OS and Birdseye views I would say the A56 is a "simple" structure to deal with and the bridge over the Ship Canal is the problem.

If you actually visit the site of the area where the bridge over the Manchester Ship Canal is bridged, you can see see how much cost would be involved at 2011 prices to reinstate the bridge with a new metal bridgework system, which was last costed in 1964, prior to the line closure.

The cost of this, plus the relaying of all the lifted trackwork and new signalling, would far outweigh any benefit to current services that would of necessity, preclude any stops for passengers at Manchester Piccadilly.

 

[imagination]

I'd also think about getting Aberdeen-Inverness up to hourly. That's not so much a matter of full dualling as extra loops. Lengthen or move the awkward ones at Keith and Forres, and perhaps consider some new ones in between stations. The only bits that really need dualling are Aberdeen-Dyce and Inverness-Nairn, which would make it possible to build a station at Inverness Airport (at last!).

You would need to redouble either Elgin to Keith or Elgin to Forres for this to work well (either of which can be done with a few mins wait at one stop in one direction) - if you try to get the trains crossing at Elgin you need to do both insch to inverurie and keith to huntly, or put in some crazy waiting times.

edit: modified it slightly. Trains now have no need to wait for another train to pass. However it is with moving the Keith crossing loop.

edit2: okay. here's my timetable. The 47 minute wait at Inverness is annoying but unavoidable, as far as I can tell.

https://spreadsheets.google.com/spr...D7qhPdFJ5bG8wUUhtbEUxX0JjM2xxaVFrR0E&hl=en_US

The letters indicate specific trains. Unmarked trains are ones to/from Glasgow/Edinburgh. Train g can go off and do something else in the day, or sit in storage. 2 trains stay the night at Elgin, one on each platform. The platform is not needed for passing so the trains can sit there for a while if needed. I havent factored in any goods paths but I'm sure that wouldn't be an issue.

The timetable would require:
-Inverness to Nairn doubled
-Elgin to Forres doubled
-Keith passing loop moved to be on the station
-Dyce to Aberdeen doubled

giving:
- one train per hour aberdeen - inverness
- one train per hour aberdeen - dyce
- one train every other hour edinburgh/glasgow - inverurie
- extra trains in the peaks between elgin and inverness