Gradient Data

[Ian J.]

In my current spate of 'something to do' activity, I'm trying to modify and improve on some gradient profile drawing code I found on 't web. Annoyingly, I don't have any accurate height/gradient data to help with getting it right.

 

Does anyone know of a source of reasonably accurate gradient and height data for railway lines in this country?

 

TIA

[keefer]

Line gradients used to feature in the Sectional Appendix, but this was by no means comprehensive.

Presumably Network Rail will have the data, but whether it's generally available on t'web is another story

[stovepipe]

There is this, I don't have it so not sure how good it is.

 

http://www.ianallanpublishing.com/gradients-of-the-british-main-line-railways.htm

 

You may also be able to find some info via the Rail Performance Society

[Edwin_m]

This is one of the items of Network Rail information that is only available on payment of a subscription (Five Mile Diagrams).  I don't know how much but would expect it to be hefty. 

[St. Simon]

This is one of the items of Network Rail information that is only available on payment of a subscription (Five Mile Diagrams).  I don't know how much but would expect it to be hefty. 

 

Hi,

 

I don't know of a way to get Five Mile Diagrams from Network Rail, besides, these don't have the exact start and end positions of gradient stated on them (although they are scaled), NR does have a full database of all gradient information, but this is only available to employees in certain position, such as designers.

 

Simon

[Ian J.]

There is this, I don't have it so not sure how good it is.

 

http://www.ianallanpublishing.com/gradients-of-the-british-main-line-railways.htm

 

You may also be able to find some info via the Rail Performance Society

 

Thanks for those. If I can I will give the book a look before buying. I expect it's reprints of the gradient profiles from 1947, and I'm not sure they're accurate enough for what I need. The RPS might be a starting point for actual data, I'll contact them to see where I get. I might also try contacting NR, but as said, I expect that to get the data I'd like, there would probably be a fee and they might not be willing even then to provide to a private individual.

 

Ta to everyone for replying.

 

Edit: something else I've just thought of - I wonder if any records of line data from the constituents of NR would be held by the likes of the NRM, National Archives or British Library?

[Mike Storey]

I had a copy of the Ian Allen gradient profiles book in the 1970's, which I have long ago mislaid, but from recollection, it gave ruling gradients over 5 or 10 mile sections, but not the detail we came to use in the Sectional Appendices, once I joined BR. However, well worth a fiver or so if you can pick one up on ebay or similar.

 

You have not said why you want the info. In the actual world, we used for it two reasons - train load/power/braking requirements, which became less relevant over time as locos and maximum loads became more standardised, so were consulted eventually only for exceptional or unusual movements, and for drainage design. Ruling gradients are the only ones that matter to operators, and actuals in detail only to the civil engineers. Drivers will know by route learning and experience where they have to open up and where they have to brake early, but they rarely know the actual gradient percentage or ratio on each stretch these days. This was much more relevant for steam locomotion.

[Edwin_m]

I have a copy of the Ian Allan route from the 70s, which appeared not to have been updated since the Beeching era including various main lines that had closed in the meantime.  I believe it was later re-released explicitly as a historic version.  The scale is about 5mm per mile so although all the gradients are marked the positions of the changes of gradient can't be established to an accuracy of much better than a quarter of a mile. 

[Ian J.]

...You have not said why you want the info...

 

I'm currently creating a fictional history for a 'maybe one day it'll happen' project (see my blog), and part of that includes planning the line, including creating a map and a gradient profile. I've drawn up a pencil and paper version, but it's messy and not to any standard. So to do a better job, I went searching online and found an HTML5 canvas-based, javascript-generated gradient profile 'generator' that I'm re-working (and I feel improving) the code of. In order to get it to work according to some kind of consistent standard like the profiles such as are likely in the Ian Allan book, it would be useful to have known accurate data for a line with it's profile so my final output can as closely as possible look 'right'. Once I know it's working satisfactorily then I can input my fictional line's data to it and get a profile out.

 

I'm also going to have a go at using the same environment to create a top down map of the fictional line, though that's quite a big thing to take on as I have nothing pre-existing to work to.

[The Stationmaster]

There is this, I don't have it so not sure how good it is.

 

http://www.ianallanpublishing.com/gradients-of-the-british-main-line-railways.htm

 

You may also be able to find some info via the Rail Performance Society

 

The older versions are pretty good although the scale is small and it is only mainlines (some of which are long vanished assuming it is a reprint of the earlier editions).  I believe it was originally done from either RCH or, more likely, official BR information and certainly in respect of places with which I am familiar it is as accurate as the official gradient charts issued to signalboxes.

[Mike Storey]

The older versions are pretty good although the scale is small and it is only mainlines (some of which are long vanished assuming it is a reprint of the earlier editions).  I believe it was originally done from either RCH or, more likely, official BR information and certainly in respect of places with which I am familiar it is as accurate as the official gradient charts issued to signalboxes.

 

.... Mike has reminded me that of course I forgot to mention, in respect of boxes, the gradients were relevant to unbraked or partially fitted trains in past times, which would require braking applications by the guard on the steeper inclines downhill (as well as relevant actions by drivers to prevent "snatching" at the peak and the troughs), and when stopped, would need a percentage of wagons pinned down to prevent running away, or chocks if unfitted. In certain areas, unfitted trains would be prohibited without brake tenders or similar. In that respect, detailed knowledge of gradients on each line, and on sidings, were essential.

 

More recently, as the standard is for all trains to be fully and continuously braked, such trains would be treated as "exceptional", such as for the movement of scrapped wagons or movements of stock without working brakes, and specific restrictions or additional measures would be prescribed for their movement. This is partly why preserved or scrapped stock movements can be so expensive (in addition to the base track access charge), or even impossible due to the maximum speeds applied and lack of paths, and that so many are now moved by road.

[Guy Rixon]

The surveyed route for a line, presumably including gradients, would surely have been part of the paperwork submitted to get the line's act of parliament. I would expect the papers to be in the national archives.

[LMS2968]

The surveyed route for a line, presumably including gradients, would surely have been part of the paperwork submitted to get the line's act of parliament. I would expect the papers to be in the national archives.

Although in many cases subsidence will have altered the profile quite a bit. The current profile for the Liverpool & Manchester is very different to that of 1830.

 

[Ian J.]

I've posted a version of my fictional line's gradient profile on my blog. I'll repeat it here for general viewing too:

 

Any feedback gratefully received.

[Edwin_m]

Nice profile, obviously a challenging route!  I think something is slightly awry with your "level" at MP145-146! 

[Ian J.]

I think something is slightly awry with your "level" at MP145-146! 

 

I hadn't noticed that. Talk about code and data blindness. I will look into it and see why it's come out that way.

[Ian J.]

Fixed

 

[28XX]

Can you provide a link to the software you used to create this?

[Ian J.]

Can you provide a link to the software you used to create this?

 

Er, can't. It's entirely on my local PC. It uses raw javascript with data manipulated in a spreadsheet to get it in the right form then pasted into the javascript file. If I could get myself back online normally with my own web server, I'd have a go at making it something users could access and create their own gradient profiles, but for now that's not possible due to my current dire living arrangements.

[LMS2968]

_{I drew those on AutoCAD, but it's a hell of an expensive package just to draw gradient profiles!}

[PaulG]

Hi,

 

I don't know of a way to get Five Mile Diagrams from Network Rail, besides, these don't have the exact start and end positions of gradient stated on them (although they are scaled), NR does have a full database of all gradient information, but this is only available to employees in certain position, such as designers.

 

Simon

Towards the end of the BR period I was responsible for the concept of the "5 mile line diagrams" and it took us 20 years to map all 10,000 route miles sourcing funding from BR,Railtrack, NR,TOCs, consultant's,contractors etc. All the data was from official sources including start /finish of gradients. The copyright for the diagrams is with a engineering consultancy, from which I recently retired.

 

The one interesting feature we found was that mile posts on the railway were invariably not 1760 yards apart!

Paul

[Edwin_m]

And most useful they are sir! 

[Ian J.]

Using a bit of guesswork around the measurements taken directly from a print of an image of a hand-drawn picture found online, this is my 'estimated' gradient profile for the Isle of Wight Steam Railway:

 

 

The same picture also included curve information, so I'm going to have a go at recreating the alignment of the line as per an overhead map, as a test to see how close I can get it (which is the reason for this thread: http://www.rmweb.co.uk/community/index.php?/topic/115868-curves-and-how-they-are-measured/)

[kevinlms]

Although in many cases subsidence will have altered the profile quite a bit. The current profile for the Liverpool & Manchester is very different to that of 1830.

 

Interesting, just wondering about subsidence. The 1830 diagram was that a designed or actual diagram? I can understand that the section over Chat Moss could even vary a fair bit. But why is the Liverpool end, so different was mostly 1in 48, now 1 in 93. That is less than 1/2 the 1830 grade.

[LMS2968]

A lot of it was subsidence: coal mining was very common along the western end of the route. The end points are not the same: the 1830 western terminus was Park Lane (Wapping) with a branch to Crown Street. The later profile shows the current terminus at Lime Street on a completely different alignment. In 1830 the line ran eastwards as far as Liverpool Road, but the later extension (from Ordsall Lane Junction) took it into Victoria station, shortened for a while to Exchange station.

 

The two diagrams are arranged to exactly the same scale and alignment, and the 1830 one use station names of the period; these often changed later. If overlaid it will be seen that most stations are exactly in line, But Edge Hill on the Park Lane alignment was slightly west of the current one. Kendrick's Cross also moved westwards to become Rainhill.

 

The 1830 profile is adapted from the British Rail publication accompanying 'Rocket 150' and gives the gradient of Sutton Inclined plane as 1 in 89. Other sources state 1 in 96, which would be a mirror image of the Whiston Incline.