Any news on proposals to build an alternative route between Exeter & Plymouth?

[MarkyT]

Meldon Viaduct is actually two structures inter-twinned. I think height was the deciding factor here, plus lower capital cost rather than any instability issues. It is a scheduled monument so cannot be demolished. It was last repainted in the early 1990s, and was strengthened in 1960 to take rebuilt WC / BB locos. Network Rail stated in the report produced after the Dawlish debacle that a new structure would be required alongside.

The structure continued to be used as a headshunt for the quarry and was also used by construction lorries for the nearby reservoir. If still broadly in the condition to carry a fully loaded stone train pulling out, albeit at very low shunt speed, it might to be able to handle lighter passenger trains at a moderate pace of say 20mph. If there was a 'Meldon Parkway' station at the west end of the bridge, accessed via the B3260 intersection from the A30, the speed reduction might not have a significant effect on journey time. The 1990s work on the bridge in connection with the Granite Way was more than just a repaint and new deck construction apparently. They carried out some structural steel and abutment repairs as well, but that would have been for it's future lighter pedestrian duty rather than continued rail use. Just speculation on my part but it's plausible they might have removed any non-authentic later strengthening elements no longer required, or replaced them in lighter form. A new bridge alongside would be much preferable undoubtedly, perhaps the only practical solution if it can be afforded.

 

[Charlie Smythe]

The structure continued to be used as a headshunt for the quarry and was also used by construction lorries for the nearby reservoir. If still broadly in the condition to carry a fully loaded stone train pulling out, albeit at very low shunt speed, it might to be able to handle lighter passenger trains at a moderate pace of say 20mph. If there was a 'Meldon Parkway' station at the west end of the bridge, accessed via the B3260 intersection from the A30, the speed reduction might not have a significant effect on journey time. The 1990s work on the bridge in connection with the Granite Way was more than just a repaint and new deck construction apparently. They carried out some structural steel and abutment repairs as well, but that would have been for it's future lighter pedestrian duty rather than continued rail use. Just speculation on my part but it's plausible they might have removed any non-authentic later strengthening elements no longer required, or replaced them in lighter form. A new bridge alongside would be much preferable undoubtedly, perhaps the only practical solution if it can be afforded.

Interesting point. Although Network rail themselves have stated that a new structure would be required and they aren't going to say that if there was even a slim chance of the old one being saved as a new structure will cost a serious amount of money. Over the 25 years or so since that work was done in 90s, its condition will of only deteriorated. I think it's safe to say that Meldon Viaduct as we know it won't be carrying any trains ever again.

 

[yorksrob]

That's interesting, I'd have to say I'm glad that proposal for Ribblehead didn't come off though!

Getting back to Meldon, because of the fortunate way it is situated I'm somewhat sure that a replacement structure could sit reasonably discretely alongside the downside of the current structure without changing the appearance to much when viewed from the Northwestern side, having said that the view from there seems to be getting more and more obscured by trees these days so perhaps it's not so important anyway?

Yes, so am I!

I agree, something sleek and stylish could be built alongside - afterall, they built a road bridge alongside the Forth bridge !

Settle might be a good place to learn about ground conditions...

I would think a new viaduct parallel to Meldon would have to be "sympathetic" to the existing structure.

Are/were there any other metal viaducts on the former LSWR route west of Exeter? The crossing of the Tavy estuary south of Bere Ferrers is metal, as I think was at least one viaduct on the former section east of St Budeaux. But between those and Meldon are the masonry viaducts at Shillamill and Tavistock, so I don't think we can conclude that the builders adopted metal construction as standard.

Lake viaduct is also masonry, as is one East of Okehampton, although I can't remember its name.

 

[Charlie Smythe]

What a nightmare of a site it would be though for construction traffic during the build process, railway line on one side and muddy field on the other.

 

[Ash Bridge]

Yes, so am I!

I agree, something sleek and stylish could be built alongside - afterall, they built a road bridge alongside the Forth bridge !



Lake viaduct is also masonry, as is one East of Okehampton, although I can't remember its name.

I think that one is Fatherford Rob, another one barely visible compared to a few decades back thanks to overgrown foliage on one side and that dual carriageway they plonked next to it on the other.

What a nightmare of a site it would be though for construction traffic during the build process, railway line on one side and muddy field on the other.

Then again they seemed to manage without too much problem back in 1874 and that was without any of today's advanced construction machinery, although I do acknowledge that quite probably there were the (more than) occasional fatalities during the building of the early railways sadly.

 

[allaction]

I recall that the Meldon viaduct, and its regular engineering inspection, was featured on the relevant episode of 5’s railway walks series this autumn.

I’m afraid that I can’t recall the name of the programme, or its conclusions.

Useless, I know!

 

[Charlie Smythe]

I think that one is Fatherford Rob, another one barely visible compared to a few decades back thanks to overgrown foliage on one side and that dual carriageway they plonked next to it on the other.


Then again they seemed to manage without too much problem back in 1874 and that was without any of today's advanced construction machinery, although I do acknowledge that quite probably there were the (more than) occasional fatalities during the building of the early railways sadly.

That's what people forget about when they complain that construction takes so long. 100 years ago if someone died that was that and everyone carried on, now, if someone died building this new bridge then of course there would be investigations and the project would be shut down for a very long time while people were sued and fined for millions. Still a challenging site though. Especially when they need 700 odd tonnes on the muddy field.

 

[Charlie Smythe]

I recall that the Meldon viaduct, and its regular engineering inspection, was featured on the relevant episode of 5’s railway walks series this autumn.

I’m afraid that I can’t recall the name of the programme, or its conclusions.

Useless, I know!

Yes it was. I watched it. They just checks bolts and replace if necessary.

 

[Ash Bridge]

That's what people forget about when they complain that construction takes so long. 100 years ago if someone died that was that and everyone carried on, now, if someone died building this new bridge then of course there would be investigations and the project would be shut down for a very long time while people were sued and fined for millions. Still a challenging site though. Especially when they need 700 odd tonnes on the muddy field.

Fair comment, I could imagine though that Rail could well be used to get a lot of construction materials to the site should it ever happen, plenty of room and sidings still in place at what was Meldon Quarry.

 

[Charlie Smythe]

Fair comment, I could imagine though that Rail could well be used to get a lot of construction materials to the site should it ever happen, plenty of room and sidings still in place at what was Meldon Quarry.

It is true. This is why project like this takes time as its not just building it, its the logistics associated with it as well. Another reason why the costs can sky rocket.

 

[Charlie Smythe]

Wonder what type of bridge it will be? Tied arch, truss or beam springs to mind.

 

[Busaholic]

I agree, something sleek and stylish could be built alongside - afterall, they built a road bridge alongside the Forth bridge !

A bit more locally, they built a road bridge alongside Brunel's masterpiece over the Tamar, although not everyone would describe it as sleek or stylish, and even fewer would claim it complements the rail bridge!

 

[Brush 4]

Worth doing a cycle trip from Okehampton westwards. Good views from the viaduct, although the trees really need some management as they are slowly overwhelming the area. That applies to many rail lines of course. There are seats at intervals towards Lydford and Meldon Junction is traceable. I've always thought that a replica of the signalbox there would make a nice viewing point/shelter/museum. The path leaves the line before Lydford and roads have to be used into the village.

 

[yorksrob]

A bit more locally, they built a road bridge alongside Brunel's masterpiece over the Tamar, although not everyone would describe it as sleek or stylish, and even fewer would claim it complements the rail bridge!

I don't know, I think all suspension bridges do have a certain attractiveness and grandiosity about them. We don't use them for railways, so I don't know what we'd end up with at Meldon.

 

[yorksrob]

I think that one is Fatherford Rob, another one barely visible compared to a few decades back thanks to overgrown foliage on one side and that dual carriageway they plonked next to it on the other.

Ah yes, that's the one. Not many pics of it on the internet, presumably because of the foliage !

 

[Cliveblackpool]

The structure continued to be used as a headshunt for the quarry and was also used by construction lorries for the nearby reservoir. If still broadly in the condition to carry a fully loaded stone train pulling out, albeit at very low shunt speed, it might to be able to handle lighter passenger trains at a moderate pace of say 20mph. If there was a 'Meldon Parkway' station at the west end of the bridge, accessed via the B3260 intersection from the A30, the speed reduction might not have a significant effect on journey time. The 1990s work on the bridge in connection with the Granite Way was more than just a repaint and new deck construction apparently. They carried out some structural steel and abutment repairs as well, but that would have been for it's future lighter pedestrian duty rather than continued rail use. Just speculation on my part but it's plausible they might have removed any non-authentic later strengthening elements no longer required, or replaced them in lighter form. A new bridge alongside would be much preferable undoubtedly, perhaps the only practical solution if it can be afforded.

The North Meldon Viaduct was built first, and the South one added a few years later in a slightly different design. They are linked together to support each other (sway etc) The North one has been reinforced and probably the stronger one. This one was used for the head shunt for the quarry.
The South one has had a new concrete deck and used by heavy stone lorries building Meldon reservoir. It is now used by the 'Granite Way foot/ cycle path. The North viaduct I think is oou, and has its original timber deck etc which needs replacing.
Mentioned in an earlier post a suspension bridge would look best but replies on this thread state rail and suspension have problems which is correct, but Japan now have road rail suspension bridges. Probably require lot of over-engineering.
(£24m to Arriva beggars belief, regarding their extremely disappointing service on Northern Rail, they need take back the franchise. Costing Manchester, Blackpool etc etc......... millions in lost business)

 

[MarkyT]

The North Meldon Viaduct was built first, and the South one added a few years later in a slightly different design. They are linked together to support each other (sway etc) The North one has been reinforced and probably the stronger one. This one was used for the head shunt for the quarry.
The South one has had a new concrete deck and used by heavy stone lorries building Meldon reservoir. It is now used by the 'Granite Way foot/ cycle path. The North viaduct I think is oou, and has its original timber deck etc which needs replacing.
Mentioned in an earlier post a suspension bridge would look best but replies on this thread state rail and suspension have problems which is correct, but Japan now have road rail suspension bridges. Probably require lot of over-engineering.
(£24m to Arriva beggars belief, regarding their extremely disappointing service on Northern Rail, they need take back the franchise. Costing Manchester, Blackpool etc etc......... millions in lost business)

The Oresund link between Denmark and Sweden incorporates a cable-stayed rail bridge for one section. The earlier 25th April Bridge, in Lisbon Portugal is a classic suspension design and had a pre-planned railway added some years after original construction. I believe cable-stayed is preferred today over suspension. Cable stayed is claimed to be more maintainable and repairable, with multiple separate cables descending at varying angles from the towers to positions along the deck rather than a pair of main cables slung between the towers with many individual vertical dropper cables supporting the deck. There is thus no single point of failure in cable stayed and recent road bridges supplementing/replacing suspension designs in UK, such as Severn and Forth have all been this design.

However I think something simple and understated in steel/concrete that reflects the original design in some ways, but doesn't overwhelm it, would be more suitable for Meldon, as there's no great expanse of water that requires a wide tower spacing.

 

[Charlie Smythe]

The North Meldon Viaduct was built first, and the South one added a few years later in a slightly different design. They are linked together to support each other (sway etc) The North one has been reinforced and probably the stronger one. This one was used for the head shunt for the quarry.
The South one has had a new concrete deck and used by heavy stone lorries building Meldon reservoir. It is now used by the 'Granite Way foot/ cycle path. The North viaduct I think is oou, and has its original timber deck etc which needs replacing.
Mentioned in an earlier post a suspension bridge would look best but replies on this thread state rail and suspension have problems which is correct, but Japan now have road rail suspension bridges. Probably require lot of over-engineering.
(£24m to Arriva beggars belief, regarding their extremely disappointing service on Northern Rail, they need take back the franchise. Costing Manchester, Blackpool etc etc......... millions in lost business)

What are the issues with railways and suspensions bridges? Is it simply just the fact that suspensions bridges sway in the wind and this can dislodge the track.

 

[Charlie Smythe]

Important to remember that Meldon Viaduct is only 165m and a new structure wouldn't be much longer so we shouldn't be expecting a Golden Gate style land mark in any way.

 

[MarkyT]

What are the issues with railways and suspensions bridges? Is it simply just the fact that suspensions bridges sway in the wind and this can dislodge the track.

There were a number of early suspension bridges that carried lighter weight metro and interurban railways in the USA, but I believe all of these rail systems have since been closed and the former rail alignments used for additional road lanes.

Proper heavy rail on suspension (or cable stayed) with 20t plus axle loads and long freight trains possible are a more recent development.

 

[MarkyT]

Important to remember that Meldon Viaduct is only 165m and a new structure wouldn't be much longer so we shouldn't be expecting a Golden Gate style land mark in any way.

Agreed and you don't want to upstage the historic monument either.

 

[edwin_m]

The 1990s work on the bridge in connection with the Granite Way was more than just a repaint and new deck construction apparently. They carried out some structural steel and abutment repairs as well, but that would have been for it's future lighter pedestrian duty rather than continued rail use. Just speculation on my part but it's plausible they might have removed any non-authentic later strengthening elements no longer required, or replaced them in lighter form. A new bridge alongside would be much preferable undoubtedly, perhaps the only practical solution if it can be afforded.

I can't help thinking if it needed work doing to support pedestrians/cyclists then it would need a lot more doing to support trains.

Cable stayed is claimed to be more maintainable and repairable, with multiple separate cables descending at varying angles from the towers to positions along the deck rather than a pair of main cables slung between the towers with many individual vertical dropper cables supporting the deck. There is thus no single point of failure in cable stayed and recent road bridges supplementing/replacing suspension designs in UK, such as Severn and Forth have all been this design.

Also suspension bridges need huge anchors at each end of the cables, which between them bear much of the weight of the bridge. In a cable-stayed bridge the loads either side of the towers balance each other and no such anchor is needed. However the bridge deck is in compression from the horizontal components of the forces in the angled cables, which means it has to be much more rigid than a suspension bridge, and this suits the heavier loads found on railways.

There were a number of early suspension bridges that carried lighter weight metro and interurban railways in the USA, but I believe all of these rail systems have since been closed and the former rail alignments used for additional road lanes.

The Manhattan Bridge in New York still carries subway tracks.

Meldon Viaduct is curved, but both cable-stayed and suspension bridges have to be straight. Looking at the local topography, trying to engineer a straight section here would involve significant diversion off the original alignment and unless you could build it through the quarry the span would be much longer too.

 

[Charlie Smythe]

Meldon Viaduct is curved, but both cable-stayed and suspension bridges have to be straight. Looking at the local topography, trying to engineer a straight section here would involve significant diversion off the original alignment and unless you could build it through the quarry the span would be much longer too.

Maybe a simple beam bridge will be used then. Also, don't forget that Meldon Viaduct is on a gradient of 1 in 76 or 1.31% just to make it a little more challenging. Having a level bridge would be easier however then that would increase the gradient to the west of the structure.

 

[randyrippley]

just rebuild it in place, same design, modern materials.
The design works, so just reuse it with modern rustproof steel

 

[Ash Bridge]

just rebuild it in place, same design, modern materials.
The design works, so just reuse it with modern rustproof steel

I don't think that's doable, as MarkyT points out the current structure is a listed monument.

Just come a across some shots I took of Meldon Viaduct in June 2015, 1st view is of north side, 2nd shows the south structure, both look in very good order cosmetically at least.

 

[randyrippley]

I don't think that's doable, as MarkyT points out the current structure is a listed monument.

Just come a across some shots I took of Meldon Viaduct in June 2015, 1st view is of north side, 2nd shows the south structure, both look in very good order cosmetically at least.

It wouldn't be the first time a listed monument has been replaced by a facsimilie.
You could regard it as the same bridge heavily repaired. After all, if it were a locomotive just about all of it would have been replaced over the same time scale, but its still the same loco...........
It would be interesting to know how much has already been already replaced over the years

 

[Meerkat]

Would a direct rebuild even be legal?

 

[deltic08]

Station is blocked by the local councils offices, nothing you can do about that. A new, improved and most likely a great capacity station will be built in another location.

Locals can use their cars to the station, but how central is the new station to Tavistock for those who want to visit?

 

[MarkyT]

Locals can use their cars to the station, but how central is the new station to Tavistock for those who want to visit?

I think it is approx. 1km from the town centre viaduct, just Plymouth side of the missing bridge over Callington Road (A390), but well sited for the massive new housing development. It would be more useful if (as a simple stub branch line) it was extended to a second station just before the viaduct with good links down to the valley floor, perhaps using a lift, funicular or some kind of rubber tyred shuttle pod. Such extension this would require replacement of the missing bridge and acquisition and demolition of a single dwelling built on the trackbed just north of the A390. The remainder of my extension is clear with all bridges intact and in use as a footpath, so could probably accommodate a single track alongside the path on the formerly double track alignment. If a through route towards Okehampton ever materialises, the council office obstacle would have to be removed and perhaps a new station could be established in that vicinity instead, but again some kind of assistance for pedestrians to climb the considerable height difference from the town centre would be useful.

 

[MarkyT]

For the through route to Okehampton there are also a series of houses on the alignment between the north end of the town viaduct and the old station buildings. These would also have to be removed along with the council offices situated Exeter side of the old station.