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UK Railway Gradients
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Joseph_Locke
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The information (officially) lives on the Signalling Plans and as a set of fields in (I think) TRATIM. Unoffically, there are books of gradient daigrams for sale on the open market, but the data in these NEVER gets updated. For major projects we use topograpical survey data to confirm signal to signal gradients.
The Planner
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TRATIM? as in the old tables for calculating SRTs? They aren't on those.
edwin_m
Veteran Member
Five Mile Plans include gradient information, but these aren't publically available.
Do you mean the gradients of existing track, or the rules which limit the gradient of new track?
civ-eng-jim
Member
1 in 80 is the normal maximum gradient but exceptional values are allowed and exist out there on the network and are perfectly acceptable with modern multiple unit stock. Lickey Incline is 1 in 55, the Channel Tunnel Rail Link has 1 in 40 gradients et cetera.
The following group standard has it in:
http://www.rgsonline.co.uk/Railway_...re/Railway Group Standards/GCRT5021 Iss 5.pdf
Section 2.7
The following group standard has it in:
http://www.rgsonline.co.uk/Railway_...re/Railway Group Standards/GCRT5021 Iss 5.pdf
Section 2.7
The Planner
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Lickey is 1 in 37.
You want
BR Main Line Gradient Profiles Paperback 26 Sep 1998
by Ian Allan Publishing
Which I see is on Amazon. It's a large-format hardback book. They have done various editions over the years (mine is from the 1960s). Detailed engineering sectional diagrams of gradients on all main routes. This book is all completely official and can only have been published with the co-operation of the Civil Engineering management of the railway.
BR Main Line Gradient Profiles Paperback 26 Sep 1998
by Ian Allan Publishing
Which I see is on Amazon. It's a large-format hardback book. They have done various editions over the years (mine is from the 1960s). Detailed engineering sectional diagrams of gradients on all main routes. This book is all completely official and can only have been published with the co-operation of the Civil Engineering management of the railway.
I mean what is the rules which limit the gradient of new (projected) track. On what it depends? I have to make some design of railway and I have no idea how to determine the maximal value of the gradient.
Thank You very much for help.
Joseph_Locke
Established Member
Freight-carrying lines should be 1 in 125 or flatter, which is a limit caused by coupling strength on 775m long trains
--- old post above --- --- new post below ---
Forgive me, I'm only one of the great unwashed ... these new fangled computation devices are all new.
civ-eng-jim
Member
Ooops. That'll teach me to believe 5 mile diagrams!
Is it only regulation about gradient in the UK railways?
Does it depend on type of pway?
The Planner
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Ha! some of us still trust TRATIM over the new stuff.
You'll find current gradient data in the spreadsheet linked at the bottom of this page:
http://www.safety.networkrail.co.uk...ety/National-RRV-Safety-Improvement-Programme
The Planner
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Only shows greater than 1 in 75 though, not every gradient.
The document Jim linked to is the current standard
Section 2.7 "Vertical alignment" is the main section on gradients. It's about 1 page long.
Section 2.8 "Track geometry requirements for sidings" includes 2.8.2 "Vertical alignment"
Section 3.1 "Performance specification for the track system" sets out the maximum design loads, which need to be accounted for because the track loading is higher during increases in gradient.
And finally
Appendix B "Guidance on Vertical Alignment" Page 34
dysonsphere
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not sure it is showing it as "1 in xxx"
The diagrams in this book go back to those of the 1930s which were assembled by The Railway Magazine and published in a couple of pre-World War 2 editions. The next edition was in 1947, published by the Tothill Press, who were the then publishers of the Railway Magazine.
Ian Allan published a hard-back version in 1978, and the gradient profiles appear untouched from the 1947 edition. I haven't seen a more recent edition, but I'd be surprised if any significant editing has taken place.
So while these gradient profiles cover a number of still-open lines, many of the junctions, stations and signal boxes on them have been lost. And some lines, of course, are now closed, so of historic interest only unless you tackle some of the cycle routes now based on such closed lines!
It would be interesting to have those diagrams in the Ian Allan book compared with an actual survey done nowadays using modern methods. If they were originally done in the 1930s the chances are that they were actually based on the engineer's drawings from the construction of the line. Apart from mining subsidence I wonder how much they would be found to have changed. They are sufficiently precise with minor changes over short distances that I suspect even reballasting might make a difference.
Joseph, it depends on engine power, braking power and line speed. The Lickey incline (North of Bromsgrove) is 1 in 37.5. The eastern exit from Birmingham New St is 1 in 40. In the days of steam, additional engines were needed. Modern diesel and electric trains cope alone. HS2 proposed 1 in 40 for the high speed line (up to 400km/h) and exceptionally 3.5% (1 in 28.5), presumably for lower speed sections approaching stations. You also have to consider whether trains would have to start from standstill up the incline.
Joseph_Locke
Established Member
You can't count on no signals: a freight train consisting of 775m worth of (say) HTAs weighs in at 4400t; assuming a 34.5t coupling strength limits you to 1 in 127.
Alternatively, 4400t is 44,000kN; a single 66 has a starting TE of 400kN; ignoring stiction that's a maximum 1 in 110 gradient.
Your comment about braking power is irrelevant - all vehicles with automatic brakes generate their own brake force and the signalling design will compensate for the slower application and lower brake retardation of freight trains - that's one of the reasons you might apply a differential speed.
As to HS2, the trains will still have only average low speed gradient performance because they will be geared to 185mph.
The second worksheet/Tab in the spreadsheet has all gradients, and they are expressed as 1 in ??. The one exception is that level track is expressed as zero.
I find it useful to resort the data by ELR, so that it is more geographically arranged.
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Most of the steep gradients on high-speed lines are where the trains travel at high speed. Look at the gradients onto the Medway Bridge. 1kM of (say) 1 in 40 hardly makes any difference to a 400M train at 186mph.
Apart from long drags like Lickey, there very steeps at the ends of platforms, e.g. the departure northbound from St Pancras low level and southbound from City Thameslink both run immediately into 1 in 29 slopes. Luckily both are in tunnels so railhead conditions are reliably good, but even for EMUs, that is quite a climb on which to get away and preserve some very close headways.
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