Ribblehead Viaduct

[Halifaxlad]

Having come across a fantastic video of Mayflower and a Southern Bullied crossing Ribblehead Viaduct, it did get me thinking about why this viaduct still has a single track over it and if it was possible to double track it again?

I am aware that it had structural problems and work has previously been done to it, but general searches online fail to provide anything more than minimal information.

 

[Bletchleyite]

Having come across a fantastic video of Mayflower and a Southern Bullied crossing Ribblehead Viaduct, it did get me thinking about why this viaduct still has a single track over it and if it was possible to double track it again?

I am aware that it had structural problems and work has previously been done to it.

Wasn't part of the solution to the structural issues to centre the loads by singling it?

 

[Halifaxlad]

I fully understand that but I can't help but wonder if that was a way of avoiding substantial repair work at that time, that could be done now to allow it to be doubled again. Unless of course the condition of it was that bad.

 

[furnessvale]

Wasn't part of the solution to the structural issues to centre the loads by singling it?

The latest school of thought is that putting a single track centrally down a set of arches designed for the offset loads of double track may actually be damaging to the structure.

I can't quite see it myself but it is being researched.

 

[yorksrob]

I think there's some discussion in engineering circles as to whether it might be better structurally to have the double track in the position it was designed for.

 

[Halifaxlad]

Thanks, it would be great too see it double. Although the main reason why Im keen to see it double is that I believe its holding the S+C back from fulfilling its potential.

The FOS+C want to see the line used more but when they'res a single track section in the middle I can understand why it might not be.

Until watching the video online I totally forget about that small single section over it.

 

[yorksrob]

I'm not sure it's holding the route back that much. Tunbridge Wells Central - Bo-Peep junction has a much more intensive service with four short sections of single track through tunnels.

 

[Bletchleyite]

I'm not sure it's holding the route back that much. Tunbridge Wells Central - Bo-Peep junction has a much more intensive service with four short sections of single track through tunnels.

Ormskirk-Preston has a much more intensive service and it's single-track throughout with a passing loop (which hasn't actually been used for about 20-odd years; the present two-unit service passes on the WCML). It may be a nuisance, but I don't think it's a genuine barrier. In practice, the long Absolute Block sections are probably more of a barrier.

 

[ainsworth74]

I'm not sure it's holding the route back that much. Tunbridge Wells Central - Bo-Peep junction has a much more intensive service with four short sections of single track through tunnels.

You'd also think not having it full of coal trains to/from Scotland will have freed up some capacity without doing any other infrastructure work!

 

[yorksrob]

Ormskirk-Preston has a much more intensive service and it's single-track throughout with a passing loop (which hasn't actually been used for about 20-odd years; the present two-unit service passes on the WCML). It may be a nuisance, but I don't think it's a genuine barrier. In practice, the long Absolute Block sections are probably more of a barrier.

Yes, this is probably true.

I don't know whether there is a way of shortening the block sections, short of full resignalling, but that would be the first thing to look at for increasing capacity, I would have thought.

You'd also think not having it full of coal trains to/from Scotland will have freed up some capacity without doing any other infrastructure work!

Yes, good point. I wonder whether there are enough paths freed for the aspired to passenger trains from Manchester.

BTW, I should have said Tonbridge to Bo-Peep junction in my earlier post !

 

[J Ward]

Rail, issue 870 has an article starting on page 32 on Ribblehead Viaduct. Page 36 reveals that the single track across it is under discussion as returning the second track would raise the speed limit across it. I gather, at the time, a single track was thought to reduce costs.

 

[Bletchleyite]

Yes, good point. I wonder whether there are enough paths freed for the aspired to passenger trains from Manchester.

Trains aren't generally very long on the line, so one option for trains to/from Manchester would be to portion-work them.

 

[chorleyjeff]

Thanks, it would be great too see it double. Although the main reason why Im keen to see it double is that I believe its holding the S+C back from fulfilling its potential.

The FOS+C want to see the line used more but when they'res a single track section in the middle I can understand why it might not be.

Until watching the video online I totally forget about that small single section over it.

I think doubling the track over the viaduct would be a solution looking for a proble. Spend some time around Ribblehead and it becomes obvious that there is no capacity restraint at Ribblehead.
It would be interesting to know what improvements would be needed to get back to the Midland Railway days when there were no speed restrictions or upper speed limits between Settle and not far from Carlisle.

 

[apk55]

Single track over Ribblehead viaduct should not be not be a problem unless there is a massive increase in traffic. There are similar sections of similar single track on a mainly double track line with a much more intensive service. Examples include Menai bridge, Tamar bridge and Navigation road station. A train should be able to clear the section in less than 5 minuets

 

[pdeaves]

Spend some time around Ribblehead and it becomes obvious that there is no capacity restraint at Ribblehead.

Unless the timetable solution required to avoid trains passing here means 'problems' elsewhere. Unless there is out-of-course running, it will never look like insufficient capacity at the place in question as the timetable will be planned around what is available; trains will appear when the timetable plan says so. If another track magically appears, this opens up all sorts of other timetable possibilities that may or may not actually be used. An immediate advantage could be perturbation resilience that would not appear in the timetable plan but would help keep things on time at Carlisle and Settle.

 

[Joseph_Locke]

You also now have the issue that if you do put a second track back (it was singled to try and slow down the rate at which the viaduct was collapsing, and at the time there were pretty much no trains anyway*) the whole thing will become unsafe for staff to access without a line block The parapets might require additional strengthening, also due to intervening changes in standards. I suspect you'd have to largely rebuild above the arches to get a compliant detail.

* I did smile at the mention of a design for Ribblehead - we spent many years fixing the cheapskate construction (masonry skin filled with rubble - water getting in then froze and weakened the masonry skin) used. I doubt anyone "designed" that, more like very early Contractor VE.

 

[DarloRich]

Although the main reason why Im keen to see it double is that I believe its holding the S+C back from fulfilling its potential.

What potential?

You also now have the issue that if you do put a second track back (it was singled to try and slow down the rate at which the viaduct was collapsing, and at the time there were pretty much no trains anyway*) the whole thing will become unsafe for staff to access without a line block The parapets might require additional strengthening, also due to intervening changes in standards. I suspect you'd have to largely rebuild above the arches to get a compliant detail.

* I did smile at the mention of a design for Ribblehead - we spent many years fixing the cheapskate construction (masonry skin filled with rubble - water getting in then froze and weakened the masonry skin) used. I doubt anyone "designed" that, more like very early Contractor VE.

I think posters here assume, wrongly, that what is on the nice paper designs is what happened on the ground. I bet there was no variation. I bet the contractor claimed for the specification and skimped on site

 

[Senex]

* I did smile at the mention of a design for Ribblehead - we spent many years fixing the cheapskate construction (masonry skin filled with rubble - water getting in then froze and weakened the masonry skin) used. I doubt anyone "designed" that, more like very early Contractor VE.

Was it the construction, or was it that a waterproof layer hadn't been properly maintained? "Masonry skin filled with rubble" sounds just like the thick-wall construction of mediaeval castles and cathedrals, where the space between two ashlar faces is filled with rubble masonry packed tight and set in mortar. Many of those buildings seem to have survived quite well for rather longer than the S&C viaducts have been up. Or is it really just a case of jerry-building on Batty Moss Viaduct?

 

[EveningStar]

The latest school of thought is that putting a single track centrally down a set of arches designed for the offset loads of double track may actually be damaging to the structure.

I can't quite see it myself but it is being researched.

That intrigued me, so been looking up some research papers ... thus far quickly read, well scanned through, Felice (2009) Assessment of the load-carrying capacity of multi-span masonry arch bridges using fibre beam elements, Moreira et al (2016) Reliability-based assessment of existing masonry arch railway bridges and Dulinska (2010), Evaluation of Dynamic Characteristics of Masonry Arch Bridges: Linking Full-Scale Experiment and FEM Modeling [sic]. All are coming to similar conclusions, in that failure modes are dependant upon imposed load, rise-to-span arch ratio, pier slenderness, backfill height and spandrel wall integrity. There is nothing about asymmetrical loading, so it seems that single or double track is not be a significant determinant. If I recall correctly, the strengthening works following reprieve from closure including grouting of the backfill, which will also strengthen the spandrel wall, so am presuming Ribblehead was restored to a pretty robust condition such that considerations about redoubling are more financial and operational than structural?

 

[yorksrob]

Trains aren't generally very long on the line, so one option for trains to/from Manchester would be to portion-work them.

Yes, and Hellifield is generally far enough out of the way that portions can wait a while without getting in the way.

That said, given that some trains from Leeds are already 4 carriages, would the platforms be long enough ?

 

[Bletchleyite]

I don't know the specific lengths, but I think they're generally quite long due to the number of LHCS specials that operate.

 

[gazthomas]

I think there's some discussion in engineering circles as to whether it might be better structurally to have the double track in the position it was designed for.

I saw that very point in a recent article in RAIL magazine

 

[70014IronDuke]

That intrigued me, so been looking up some research papers ... thus far quickly read, well scanned through, Felice (2009) Assessment of the load-carrying capacity of multi-span masonry arch bridges using fibre beam elements, Moreira et al (2016) Reliability-based assessment of existing masonry arch railway bridges and Dulinska (2010), Evaluation of Dynamic Characteristics of Masonry Arch Bridges: Linking Full-Scale Experiment and FEM Modeling [sic]. All are coming to similar conclusions, in that failure modes are dependant upon imposed load, rise-to-span arch ratio, pier slenderness, backfill height and spandrel wall integrity. There is nothing about asymmetrical loading, so it seems that single or double track is not be a significant determinant. ...

I'm not at all sure about the exact meaning of all the terms being used here in bridge design - but there is something about "imposed load" - and with double track, you would have, potentially, double the imposed load of a single track line ie the mass of two tracks+ ballast and two trains, surely?
Plus, possibly, some dynamic component x 2?

Was it the construction, or was it that a waterproof layer hadn't been properly maintained? "Masonry skin filled with rubble" sounds just like the thick-wall construction of mediaeval castles and cathedrals, where the space between two ashlar faces is filled with rubble masonry packed tight and set in mortar. Many of those buildings seem to have survived quite well for rather longer than the S&C viaducts have been up. Or is it really just a case of jerry-building on Batty Moss Viaduct?

True, but those buildings have not had (at various times) 1,000 tonne trains running over them at speeds of 50 mph and more. Kind of introduces a totally different aspect to the problem I should think - even if the viaduct is designed for that from the start.

Yes, and Hellifield is generally far enough out of the way that portions can wait a while without getting in the way.

That said, given that some trains from Leeds are already 4 carriages, would the platforms be long enough ?

Platforms at Hellifield or elsewhere? ISTR back in the day with the Thames-Clyde that trains would draw up at Settle and - I think - Appleby. We are not likely to get trains as long as 9 or 10 x Mk1s though, even in the starriest eyes, surely?

And are we talking about through services from Manchester to Carlisle, or just extended locals to Hellifield or Settle? If the latter, surely putting in a crossover at Settle would be far cheaper than doubling Ribblehead viaduct?

 

[Bletchleyite]

I'm not sure what the long-term plan would be, but isn't the short-term one just extending roughly half the Clitheroe terminators to Hellifield?

 

[Ploughman]

* I did smile at the mention of a design for Ribblehead - we spent many years fixing the cheapskate construction (masonry skin filled with rubble - water getting in then froze and weakened the masonry skin) used. I doubt anyone "designed" that, more like very early Contractor VE.

I was going to make the same point "Was it actually designed?"
However you could also say the same thing about many highway bridges going back to Roman times.
I think a lot of "Rule of Thumb" Construction has taken place in the past.

 

[Bletchleyite]

I was going to make the same point "Was it actually designed?"
However you could also say the same thing about many highway bridges going back to Roman times.
I think a lot of "Rule of Thumb" Construction has taken place in the past.

Most likely, though the upside of that kind of construction is that things were usually hugely overspecified - and if they weren't they would soon fall down.

In the modern era it only tends to be DIYers who do that.

 

[BantamMenace]

Trains aren't generally very long on the line, so one option for trains to/from Manchester would be to portion-work them.

4 cars from Leeds and 2 from Manchester is going to Leeds to a very empty 6 cars north of there.

2 from Manchester arriving at Hellifield then 4 from Leeds with only the front 4 going north might work. Leaving two at Hellifield to connect to the next 4 southbound.

 

[Baxenden Bank]

Somewhere on a DVD, there is a discussion of the works carried out to the viaduct at the time of singling.

This involved a concrete deck, with waterproofing, over the whole length of the viaduct to prevent water ingress into the 'hollow' columns i.e. backfilled with loose rubble. In order to remove the (plentiful) rain there are drainage channels which run the length of the viaduct along each side. Perhaps these reduce the usable width of the formation and prevent re-doubling?

As to frequency, isn't the longest block section about 30 minutes. So a far more frequent could be operated before it is necessary to re-double the short section over the viaduct? This to be taken in the context of the loss of the coal traffic in recent years.

 

[Ships]

You also now have the issue that if you do put a second track back (it was singled to try and slow down the rate at which the viaduct was collapsing, and at the time there were pretty much no trains anyway*) the whole thing will become unsafe for staff to access without a line block The parapets might require additional strengthening, also due to intervening changes in standards. I suspect you'd have to largely rebuild above the arches to get a compliant detail.

* I did smile at the mention of a design for Ribblehead - we spent many years fixing the cheapskate construction (masonry skin filled with rubble - water getting in then froze and weakened the masonry skin) used. I doubt anyone "designed" that, more like very early Contractor VE.

I don't think having to work green zone would be a massive issue. Also if you've guard rail from a train derailment point of view there would be no issues there, you might need to do something for the staff but if it's ok now maybe not such an issue (unless there are grandfather rights).

 

[matacaster]

Somewhere on a DVD, there is a discussion of the works carried out to the viaduct at the time of singling.

This involved a concrete deck, with waterproofing, over the whole length of the viaduct to prevent water ingress into the 'hollow' columns i.e. backfilled with loose rubble. In order to remove the (plentiful) rain there are drainage channels which run the length of the viaduct along each side. Perhaps these reduce the usable width of the formation and prevent re-doubling?

As to frequency, isn't the longest block section about 30 minutes. So a far more frequent could be operated before it is necessary to re-double the short section over the viaduct? This to be taken in the context of the loss of the coal traffic in recent years.

I also understood that there was a full width concrete deck laid to spread the load. Aside from the capacity increase, which may or may not be required in due course, other advantages of double-tracking the viaduct are

- that you eliminate two sets of points that can fail particularly in snow or ice when the nearest linesman is likely some distance and time away.
- increased speed should be allowable.