rmHawk765
Member
Ah alright, that does make some more sense.
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Single line sections that would benefit from becoming multitrack?
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Gloster
Established Member
If you mean the section at Largin over Largin and St Pinnock Viaducts, you would have to rebuild both of them as in 1963 the Chief Civil Engineer’s Department decided that it would not be advisable for two trains to be running at speed on either viaduct at the same time. The cheapest solution, remember that 1963 was not an auspicious year for BR, was to single the line, something that was simplified by having a signal box immediately adjacent. If a train did pass when you walking across the viaduct, you could feel the viaduct groaning under your feet; it was actually worst with an Up train that was accelerating away from a signal stop.
Buttsy
Established Member
In the redoubling vein, Wolvercot Junction - Charlbury East and Evesham - Norton Junction would help delays on teh Cotswold Line. Currently, only 3 tph can run between Wolvercot and Charlbury as the timings on Real Train Times shows it takes approx 16-17 mins to cover this section. The northbound and Southbound services generally pass between Ascott-underWychwood and Shipton,but any late running northbound can screw the southbound as to it's presentation time at Wolvercot, which is the main issue on the route.
The remaining short single sections on the Cornish main line are fairly manageable. The 6.5 mile section between Probus and Burngullow was far more problematic when singled in 1986, with delays to long distance traffic initiated there propagating performance pollution all over the UK. I think there were some bridge and earthwork concerns at the time like Largin, and singling avoided a major renewal of the second track. The Treasury were still paying additional grant to BR for removing 'redundant' track at the time I believe. Like many schemes of the Thatcher era, layouts were 'locked in' to these 'minimum viable product' configurations at the time of rail's absolute nadir with the lowest passenger numbers ever recorded (until COVID of course). The problem was that passenger demand soon started showing strong growth again in the late 1980s, and there was pressure to increase services, yet these often couldn't be accommodated for decades because changes to just resignalled layouts would be far too expensive and disruptive. Thankfully, Probus - Burngullow was doubled again in 2005.
Annetts key
Established Member
Of course, in some places, although there has only ever been a single line, the railway company may have bought a wider strip of land than needed, so allowing for the line to be doubled at a later date if required (and if additional funds become available).
Also, in some places, although there may not have been double running lines, there may have been long sidings running parallel to the single line.
The biggest issue with expanding or improving our current network, is that Network Rail is actually Railtrack under a “new” name (yes, different top level management and a different government funding arrangement), and there isn’t an internal mechanism for funding anything other than minor improvements (unless part of a larger scheme and then what they can do is limited). The intended role of Railtrack was to operate and maintain the existing network. Not to expand or improve the network.
Hence why external funding is needed for most large projects that involve expanding or improving the network.
Does anyone know if GBR will have authority and a budget for expanding or improving the network? Or is it too early to know?
If they do, I would expect the budget to have to come from somewhere else within their existing budget - it seems unlikely there will be 'new money' for such things, at least in the short to medium term.
I don't think they started until the late 60s?
I've no knowledge, but major capital projects (e.g. larger electrification projects) are currently funded separately to NRs control period funding system, and I don't see why that would change.
mike57
Established Member
But if the service goes half hourly timekeeping is going to suffer. On Saturday mornings there is an extra service just before lunch, this week it was late leaving York, and then lost more time waiting for the platform at Malton. I realise that its not going to be sorted, but its yet another timetable constraint on what is already a very difficult to path service (obviously thinking here the through trains to Manchester)
Dr Hoo
Established Member
The Surplus Track Capacity [indecently hasty elimination] Grants were a child of the Labour Minister, Barbara Castle, within the Transport Act 1968 during the white heat of Harold “no major rail closures” Wilson’s government. The scheme was basically one-off funding that had to be spent within five years. Unfortunately, BR regions had to ‘bid’ for the funding so they all prepared long lists of schemes that might just be eligible. This had the unintended effect of casting a very long shadow in terms of many routes having oxyacetylene torch-ready plans for drastic rationalisation when any future renewals were planned for many years afterwards.I don't think they started until the late 60s?
Peter Wilde
Member
Perhaps worth remembering that if Swiss standards of punctual running could miraculously be imported to GBR, much of the objection to short sections of single-track would disappear. If only!
dk1
Veteran Member
It already has been. Its known as Greater Anglia
jammmmmsssssss
Member
Yeah, GA have some pretty long single track sections (Sheringham and East Suffolk lines), but they never seem to cause any issuesIt already has been. Its known as Greater Anglia
dk1
Veteran Member
Thats all down to their fabulously efficient drivers.
DM352
Member
Mentioned already but the Kilmarnock line though partial redoubling happened, Kilmaurs was short sighted as a single platform on the formation. A fix would be like Thames and Haddenham rebuild so not cheap.
Berry Brow was another one bulit on an ex line formation after the singling.Less of an issue but have been stuck in the loop in the past when things a run late.
Another is the road overbridge at Poppleton for the bypass is like the Exeter M5 problem with a single span on a former double track line.
Berry Brow was another one bulit on an ex line formation after the singling.Less of an issue but have been stuck in the loop in the past when things a run late.
Another is the road overbridge at Poppleton for the bypass is like the Exeter M5 problem with a single span on a former double track line.
Fortunately in most cases where a new overbridge has been built, it usually spans the whole track bed (from my fairly unscientific observations).
Falcon1200
Established Member
The redoubling allows a half-hourly service to operate; Is there really a need for any more than that?
jammmmmsssssss
Member
Aren't you a driver on those routes lol
In similar vein but on the other side of Bristol - a short section of double track on the Beach line at Narroways Hill to hold down trains clear of the main line would help - as would an extension of the Clifton Down loop to just before Sea Mills and the Cheltenham Road viaduct. With a bit of cooperation from the council, a second platform at Redland shouldn’t require expensive lifts etc as there’s already a ramped footbridge.
daodao
Established Member
Rhiwbina to just before the pedestrian crossing east of Whitchurch station on the former Cardiff Railway could be redoubled. This would increase reliability on the Coryton branch and permit a frequency increase and/or extension to serve the new Velindre Hospital and possible park and ride facility near the M4 junction 32 interchange/Asda.
Track rationalisation and singling was the 1960s management consultant’s (or whatever they were called then) dream. Theoretical savings with no accurate means of measuring the true long-term impact (revenue potential as well as cost) and, consequently, no comeback when improvements aren’t recognised.
Compared to the 1960s improvements to rail systems, plant and machinery over the following decades mean many miles of plain line can be maintained and renewed by a smaller workforce. These efficiencies combined with, in many instances, alleviating the need for additional S&C, mean singling ‘savings’ are indeed questionable.
Businesses and public organisations have never learnt, they continue to spend ever increasing inflated sums for daft ideas and proposals where the management consultant has no responsibility or liability.
Compared to the 1960s improvements to rail systems, plant and machinery over the following decades mean many miles of plain line can be maintained and renewed by a smaller workforce. These efficiencies combined with, in many instances, alleviating the need for additional S&C, mean singling ‘savings’ are indeed questionable.
Businesses and public organisations have never learnt, they continue to spend ever increasing inflated sums for daft ideas and proposals where the management consultant has no responsibility or liability.
Annetts key
Established Member
Doubling of the existing single line between Montpelier and Narroways Hill Junction is unlikely, as I don’t see sufficient justification for this. Now that the route between Doctor Days Bridge Junction and Filton Junction is back to being a four track railway, there are less problems with the trains for the branch having to be held or holding up other traffic.
Doubling over the Cheltenham Road viaduct isn’t very likely, as there have been concerns about this bridge in the past.
Extending the existing loop at Clifton Down towards Redland, so that that station becomes two platforms again I can see as being useful. And possible and practical. The existing points are not that far from the station anyway. So the amount of new track needed is not too much. And the alterations required to the signalling shouldn’t be too difficult.
Between Clifton Down Tunnel and Avonmouth Dock Junction is the longest single line section. But more importantly, this single line section is where control of the line is divided between TVSC and St. Andrews Junction signal box. That makes changes to the signalling more difficult.
It’s quite far between Clifton Down Tunnel and Sea Mills station. That section has been single for a long time. If you want to electrify this line in the future, I’m not sure you would want to double it through this tunnel. And beyond the tunnel, some of this section is on embankments. These would all need investigating and may reveal some costly work that would be need to be done. Doubling this section would be too expensive for the small operational gain I think.
I would like to think doubling between Portway Park & Ride and Avonmouth Dock Junction may be worthwhile, but that’s not as easy as it seems either. The new station may have been built partly on the old track bed of the lifted line (it’s on the side where the lifted line was), and I don’t know if it’s possible to slew the existing line towards the river to make space for a second line. Or if there is enough space for another platform. The existing level crossing would need widening. And the signalling here is relay interlocking. Unfortunately due to a contractor wiring up the relay room heater to turn in when the room was warm, the wiring for the signalling has degraded insulation due to being cooked. Hence the signalling alterations would cost rather more than they should have. Because the whole relay room would either need rewiring or replacing.
So again, this idea is unlikely due to the costs involved.
Another possibility for this end, would be to redouble between Avonmouth station and St. Andrews Road station. Primarily because some of the existing Engine Release line between St. Andrews Junction signal box and St. Andrews Road station could be used. You would however still need to put back the lifted line between Avonmouth station and St. Andrews Junction signal box. And remove the concrete buffer stop at St. Andrews Junction signal box.
The level crossing at St. Andrews Junction signal box is due for renewal. Unless someone ensures the new crossing is specified for a two line railway, changing it again after renewal would add to the costs. The existing crossing was designed for two lines, at this was a two track railway until 1988.
As it’s currently impractical to put the removed platform back at St. Andrews Road station (unless you lift one of the freight lines), the points to go back to a single line would have to be before St. Andrews Road station. Unfortunately that’s not going to help...
So what can be done at the Avonmouth end that is not too expensive? All I can think of, is to make both lines through Avonmouth station bidirectional. Hence improving operational flexibility here. At the moment, trains that terminate here have to use the down side platform (town side). If a train arrives at the up side platform (docks side) and for whatever reason, cannot continue towards Severn Beach, there is no facility for it to change direction. It has to proceed on to the single line towards Severn Beach as that is the only signalled move available.
Similarly, if a train arrives from Bristol at the down side platform. It has to reverse, as there is no facility to continue towards Severn Beach. The signal at the Severn Beach end of the platform only has a red aspect. No provision was provided in the signalling design for anything else.
devon_belle
Member
I think the Exmouth branch is worthy of mention, if it hasn't been already. Historically the line was double track from Exmouth Junction to Topsham (inclusive), with 4 platforms at Exmouth. Re-doubling Exmouth Junction to Polsloe Bridge, preferably with a double lead junction and two platforms, would help to stop SWR and ECS GWR trains being held up in the Exmouth Junction area. I'm not sure if extending the double track at Topsham or doubling at Exmouth (i.e. a second platform) would be better for the service.
Hence “just before”.
Annetts key
Established Member
It’s worse than that.
Track mainly degrades due to wear (although wooden sleepers rot and steel rusts). Wear caused due to trains using the track. If you downgrade from a double line to a single line, the wear rate of the remaining track doubles if the same number of trains run. Which in turn half’s the remaining lifespan of said track.
Plus, if maintenance or renewal work is needed, the line has to be completely closed. Whereas with a double line, it may have been possible to have used single line working to maintain a limited service.
The real reason for lifting track in some areas, was to avoid the costs of renewing worn or life expired track. When reducing the number of lines, they generally retained the best parts, removed the worst condition parts, then slewed and joined up what was left.
Or tracks were lifted to save having to carry out expensive repairs to bridges or other structures or to save having to replace/renew bridges or other structures.
But these types of savings are a one time thing. Once a line is singled, you can’t save money by doing this again. Unless you close the line entirely.
Since then, many lines have been relaid using concrete sleepers and CWR/LWR (continuous welded rail / long welded rail). Using this type of track combined with using tampers and other track maintenance machines reduces the on going maintenance costs compared to the traditional 40 foot or 60 foot bullhead rails, cast chairs and wood pegs/metal spring clips, fishplated joints and wooden sleepers.
and on top of all that the points at both ends get lots of use and need maintaining a lot more than the other option of double plain line which can hardly go wrong!
The other big downside of singling is setting the maximum frequency of the timetable in concrete, and sometimes limitting the timetable to a single option, or ‘ossifying’ it as the regulator liked to say at the start of privatisation.
Very true. That may not matter much on an isolated branch line with almost no through running, but elsewhere, where initial delay can be imported, it can cause mayhem on the single line, sometimes for hours. Measures like long dynamic loops and intermediate signals/block markers on the single sections could permit more than one train to go through in one directional flight (or convoy), but that isn't helpful for attractive passenger frequency if two trains an hour depart 5 minutes apart, though it might be a good solution where two branch lines diverge a distance along a common section.
Short sections of single on secondary lines with moderate frequency can be manageable. Modern trains can often accelerate quickly after unexpected stops. Examples like Penzance work because any small incoming delay awaiting single line clearance can be absorbed in turnround layover. I expect signallers there give priority to departures most of the time, especially long distance ones. It's also theoretically possible to fill up the station then accept another arrival onto the single that blocks the path of any departure. The only remedy to this deadlock is to send a train empty to the depot reception road to make room for the incoming one. In reality it's improbable 4 loaded passenger departures would be lined up across the station ready and waiting for the off, but it's another reason a signaller might be rather more focused on getting departures out on time than worrying about adding a few minutes of delay to an arrival.
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This reminds me of the Little North Western, which many would have expected to have been singled at some stage, but which has retained double track. This seems to have survived with jointed track, wooden sleepers etc and has required fewer renewal works than many quieter routes.