Great Western Coffee Shop

From The BBC (https://www.bbc.co.uk/news/uk-wales-52215151)


Lots of famous inclines on UK railways - Lickey, Wath, High Peak, Folkestone Harbour - but what is the steepest on GWR services?

Rattery or Hemerdon in South Devon must rate near the top.
 

Acton Diveunder?  ;)

Exeter St Davids to Exeter Central

Cogload Junction - Down line over the flyover

I think Dainton Bank takes it, being briefly 1 in 36 before the tunnel, but it averages out at 1 in 40.

Exeter St David's to Exeter Central averages 1 in 37 over 1/2 a mile.

How steep is the London end of Portsmouth and Southsea high level?  It always feels quite a sudden gradient...

Paul

St Davids to Central in Exeter always looks flippin' steep to me (esp. if viewed down the hill from the platforms at Central).

I'm quite shocked that Dainton is nearly as steep, on average, but have never been there to observe it (and have not riden up it on a train in about 8 years).

How about the pull-up into Reading from the dive-under just to the east of the station?

Don't they split some freight trains at Exeter to get them over Dainton bank then reassemble them somewhere to go on to their destination.

I think it's one of the reasons they would like to electrify Newton Abbot to Plymouth so the passenger trains would have more power.

(http://www.mbob.co.uk/rforum/exc.jpg)

Even more dramatic from the footbridge at the far end, with a long lens!
(https://drive.google.com/uc?id=1e9mEWY7AdLsYpqprSKswJw1CAb_6QOx-)

Coombe Junction to Liskeard is 1 in 40 plus an 8 chains radius on the curves. No chance of a run-up on that!

Just to add that Acton Diveunder has a 1 in 40 descent and 1 in 50 incline (you can only go through it in one direction!), so not as steep and a lot shorter than BNM's examples.

My goodness yes ... I made the mistake of walking from Coombe Junction to Liskeard early last month.  Well - more staggering and panting up the road.

Could we please change the topic title to "Steepest Gradient on GWR" as the railway doesn't do "hills"..... ::) :P

Just for you...

The hill gradient between Coombe Junction and Liskeard.  One of the few UK cases where the railway goes a long way round to rise more gently.  See also Dduallt.

(http://www.wellho.net/pix/gradcomb.jpg)

1 in 6.25 (16%)?

Tis but a gentle slope.

www.bbc.co.uk/news/amp/uk-wales-52215151

The Tamar Valley Line has Gradients of 1 in 37 between Bere Alston and Gunnislake.

Of course, if GWR were ever to take over the running of the line between Lynton and Lynmouth...  ;D

The climb out of the Severn Tunnel

1 in 61.


1 in 90.

Forgive me if it's already been answered elsewhere but do NR have a stated maximum acceptable gradient for new builds and if so, is it less than some of the gradients they've inherited?

I have a suspicion that the new build limiting gradient would be surprisingly steep - look at how Eurostar ducks and weaves out of King's Cross.  For a station, rule are probably pretty tight on gradient and curvature.

Whilst trying to find the Acton Diveunder gradient I think I remember saying that they had to use concrete slab track due to the 1 in 40 gradient.

The modern one that is usually quoted is from St Paul’s Thameslink (aka City Thameslink) up to Blackfriars, which I think is steeper than 1 in 30. That is of course quite short, passenger only, and electrified. I remember when they revamped it to put the line under Ludgate Hill they lowered the northern abutment of the bridge over Queen Victoria Street (i.e. just north of Blackfriars) so that the bridge section was on the gradient, so they must have thought it was pretty tight.

The real game-changer is electric traction. I recommend a 323 up the Lickey, about a minute quicker than a 170 Bromsgrove to Barnt Green (start-to-pass).

I've quoted before that Crossrail has 1 in 27 in three places in its tunnels. Obviously being indoors in the dry makes that less of a problem, but I recall that some high-sped lines have around the same  gradient, and live outdoors: The Schnellfahrstrecke Köln–Rhein/Main has 4% so as to avoid wiggliness. Whether the ICE3s use any trickery to give them better grip than 50% of axles motored would suggest, I don't know.

Some years ago I managed to get a front seat with a forward view in an ICE3 along this line and the switchback nature of it was very clear. I was able to see the speedometer in the driver's cab and I was impressed to see how closely it kept to 300 km/h along the route, only dipping slightly on the upward gradients.

So, you never saw one attempt a hill start in the rain? I wonder if it could do that!

One of the less obvious effects of high-speed travel is that improves hill-climbing. An ICE3 has nothing like enough power to climb 4% with no speed loss - that alone calls for 15 MW, and it only has 8 MW in all (mostly spoken for by drag and friction). However, it has loads of kinetic energy, and can trade a bit of that for the potential energy it needs at the top of the hill. And that trade-off gets more favourable the faster it goes, which somehow doesn't sound right.

For a small time interval (hence small changes in everything else) and a height gain of h, the speed drops by 2gh/v - which gets smaller the higher the speed v (in m/s, for SI units throughout). But this trick only works for short sharp rises, so if you start at 300 km/hr, that falls to 295 for a rise of 10 m, 278 for 50 m, 254 for 100 m, and down to 200 m/s for 200 m. That assumes the traction power is just enough to maintain the actual speed on the level, but if more is available it can top up the energy lost. Those speed drops are the same for any gradient, but the gentler that is the more time there is for any surplus traction power to make up the loss.

On the Köln–Rhein/Main line the overall height range is 50-350 m, but the steep bits will be only small parts of that - I'm not sure exactly where; climbing out of valleys perhaps?

Somebody will know the answer, not GWR territory, but whats the ruling gradient of the SMR (both of them)? :D




Snaefell  Mountain Railway  ;D

Snowdon Mountain Railway  ;D

Snaefell 1:12 ruling gradient
Snowdon 1:7.86

edit
Many years ago Ian Allan published
British Main Line - Gradient Profiles covering the whole the country
17 profiles covered the GWR, which included some ex-SR and S&DR lines
Braunton to Mortehoe was around 1:40

I still have a copy of the Ian Allan Gradient Profiles, no mention in it of publication date, but it was priced at 21 shillings (that's equivalnet to 105p now), so before February 1971.

It shows short stretches approaching Dainton Tunnel of 1 in 36 (at about MP 217 ¼ ) on the Down, and I in 37 (at about MP 218) on the Up.

Edit - the actual mileposts shown in the book are 20 miles less:  I'd changed them by hand based on what I saw hanging out of the windows.

Looking on Google it seems to be 1966, which seems about right

Back in about 1993 I witnessed a Class 50 plus 6-7 coaches come to a halt on the bank between Exeter St David’s and Central (just past Bonhay Road Bridge) and then start up the gradient again as some railway staff looked on from Platform One.  It involved a large amount  of engine noise and exhaust smoke and I wasn’t entirely sure it would make it. To this day I wonder if it was done for a wager

In the early 1970's, I'd guess 1974 I was on a Peak hauled Train, load 13 MK1 coaches and Passenger full Brakes (BG), that came to a stand halfway up the Lickey incline, (I seem to remember at a Red signal, fantastic place to put a Home signal) I thought this could be interesting as I didn't think the loco could start such a Heavy load Around 440 tons without Loco weight on the gradient.
It did mange to get moving but I think we got no faster than 15mph by the top.
And I don't recall if it was a Crompton Parkinson Peak or a Brush Peak.
On another occasion a shorter Train about 9 MK1 coaches, I was surprised to find the Train got banked, by the Licky Bankers, very strange to have engines to come up behind a MOVING Train and give a shove.
Something else Mr 'Elf and Safety couldn't enjoy doing, so Mr Elf has outlawed it. :P

Mine does have dates above the Contents.

First ed 1966 then 1970,1978, PB 1983, 1997 (mine).

If you want the speed limit key you need to go to Page S1!

OTC