Marples and Beeching

pretty much - although if you look at the maps it does go near it for much further up (across Northants really) - just shows that the surveyors Watkin engaged weren't far off on the best route, but they weren't trying to build for 21st century high speed.

 

Obviously the corridor Marylebone-Aylesbury and Marylebone-Banbury is full anyway so that takes care of rest of the Met/GC and GC/GW joint lines. I don't think that had Brackley viaduct not been demolished and the housing in Brackley not been built that we'd be talking about HS2 using that bit of the route either - from memory there's a significant issue with the curves out of Brackley towards Helmdon and then those at Woodford.

 

Long forgotten dodgy source.

Its an early example of dodgy wikipedia information before wikipedia! See cartoon below. https://xkcd.com/978. There was a major struggle to get it out of the Wikipedia article on the London extension which didn't altogether succeed! Apparently Wikipedia zealots don't see accuracy as being nearly so important as Wikipedia's arcane rules.

I've seen it mentioned who the author was who first came up with it, but forget the name. It was, I gather, a major study of the railway. Whether it was a deliberate lie or just ignorance/stupidity ("Hey, it wasn't built to the current British Railways composite gauge so I suppose it must have been Berne Gauge") or what we'll probably never know, but I'm sure the widespread repetition is all about the common game of wanting to make any government decision the author doesn't like look shortsighted (or worse).

 

Emphasis on 'long forgotten'. I was thinking way before Berners-Lee and Bill Gates.

 

Oh gosh yes, I believe the offending book was written in the 60s.

 

When you're building a new line nowadays you might as well make it to continental gauge. And there may eventually be some trains of that size running on HS2, but that will not be for a long time, if ever. Meanwhile, with trains that will necessarily continue on other lines, the GC loading gauge would have been adequate.

However I take the point about curvature limiting the utility of the GC route for HS2.

 

BTW: why is this discussion in the Steam Traction section rather than General Railway Chat?

 

I think because it split from the Gresley thread - but I agree, it should move.

Tom

 

The subject is really complicated. It's nice to envisage some future transition to continental gauges, but I don't think there's the slightest chance in any foreseeable future.

Easier to say lines should be built to the largest GBR freight and passenger gauges - or structure gauges at least - but if you consider long tunnels then the extra expense must be very considerable. Is that justifiable for an extension to London Underground? Especially if the alternate to building it to current LU structure gauge looks like not building it at all? How much more does an HS2 cut and cover tunnel cost if you build it two feet wider?

It's not a new question. Felix Pole in his book complains about the waste of the GWR having increased the weight limit new bridges were built to without immediately taking advantage of it, so that there was even an example of a bridge being reconstructed a second time without ever carrying the increased load. The engineers see the logic in future proofing, the men with the money less so, and when the money is horribly tight it can be very difficult to justify future proofing. Sometimes better not to mention it [allegedly].

 

The rati0nale for building a new high-speed line to Continental gauge would be to allow for running to enough destinations (immediately on opening or at a later date) for at least some of the services to be worked by larger trains. Against that, as long as some services are necessarily worked by GB-gauge trains running onto the old lines, you need to compromise on train-to-platform distances. As for tunnels, for high speed don't you need a generous amount of space around the trains anyway?

What actually is the loading gauge for HS2?

 

It seems to me new infrastructure should be built to at least accommodate double-decked container movements. UIC copes with container lorries, but uncertain if double-stacked containers are possible. Thoughts, folks?

 

It will be built to continental loading gauge; I’m not clear how platforms will be built


Sent from my iPad using Tapatalk

 

Not keen on the Belgian solution to that issue, then?

 

My understanding is that the structure gauge for HS2 is UIC GC, as per HS1, but that the loading gauge is not GC, due to platform clearances. I think it will be something called UK1, but I'm not at all sure. Its a very complicated subject. I'm just trying to get to grips with some of it. The historical stuff is complex enough but modern gauging is worse!
Here are some of the relevant gauges.

The shadow is W6, which is pretty much the default UK freight gauge and very similar to the BR gauge from the 1950s.

I only found UK1 today, and I'm not entirely sure of its status, but it appears to be a static gauge that should cover much of the UK network. I've seen some suggestions that its to be the rolling stock gauge for HS1.

W12 is the largest UK gauge for container loads, and NR are working on upgrading as many as possible major freight carrying lines to use it. Its just a gauge for the container load, so that's why it looks smaller than W6 in places. Its easy to see that tunnels and arched bridges are the biggest challenge.

UIC GC is one of the larger European standard gauges. This is the GC *loading gauge*. I've seen reports that HS1 was built to the GC structure gauge (larger than the loading gauge of course) and that HS2 is planned to be built to GC. However the platform clearances between GC platforms and UK1 stock would be quite unacceptable.


Note that showing the static UK1 gauge is extremely simplistic. Modern passenger rolling stock, even before allowing for tilting trains* , is much more mobile on its suspension than it used to be, which must be allowed for, and the detail in the gauging of passenger trains makes my head hurt. I think only a full time industry pro has much chance of achieving a reasonable level of expertise in the subject.

*consider, for instance, that presumably the gauge must allow for a tilting train that has had the tilt jam the wrong way!

 

Look at some videos on Youtube of double-stacked containers on UP. Imagine the same with suitable clearance and pantographs! Not possible, I suspect!

 

They've triple stacked container trains in some places across the pond!

 

Yeah well, when there are hundreds of miles between over bridges things are a bit more flexible...

 

Perfectly possible - and the Indian government are busily doing so for their electrifications.

 

U
The largest loading gauge I think that can be reasonable on a railway is for double stack containers with room underneath for the running gear that is more than an ambitious minimum and room overhead for 50 kv electrification - as the “Iron Rhine” the Dutch have built something like this East from Rotterdam towards old industrial Germany and the Ruhr. In principle there is no reason it should not be extensible across the North German plain to the Baltic and through Poland. (The pantographs extended up to the overhead wire above double height containers from locomotives built to the normal loading gauge are quite an interesting sight.)

My misgiving is that containers have I changed shape getting much larger - finally higher - since their inception & might again.
My comfort is that the sort of tunnelling machine you use to bore a few miles or more invariably produces a circular tunnel, so you have elbow room for cables etc. beside straight sided containers.

Larger than this I very much doubt could be sensible if only from the cumulative axle loads - a 40 foot container might be 3 tons empty but 25 to 29 tons full is quite possible.

 

Interesting programme on Radio 4 on Easter Sunday evening (Archive on 4 - Lines of Duty), about the leaking of an internal government document in the early 1970s. The document proposed a further round of major railway closures, a sort of Beeching Mk2, apparently similar to the Serpell proposals of a decade later.

https://www.bbc.co.uk/sounds/play/m0015kqr