Download the 6th Edition PDF

Want to know how OLE works? Click the download button, save the PDF and off you go. Current number of downloads (all editions): 


This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License

The 5th edition was downloaded 38,776 times between December 2018 and August 2021.

The 4th edition was downloaded 7,838 times between November 2016 and December 2018.


Download the Traction Addendum

Since the 6th edition came out in 2021, we’ve added a new chapter explaining how electric traction works. If you download the full 6th edition here it includes that chapter.

Picture of a sample page showing text and diagram of electric train architecture

If you previously printed out the 6th edition before we added the new chapter, you can download, print and insert the extra pages in your printed copy. The PDF below includes revised Table of Contents and Table of Figures pages as well as the actual chapter. Note that this has been numbered as Chapter 23 to avoid upsetting your existing page numbering. In the full download it is Chapter 11.

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

5th Edition – Roll of Honour

Thank you to all our lovely backers, who helped turn an online-only project into an actual, physical book. We are endebted to the following people:

Zoe Alderman, Munaf Ally, Brian Armstrong, Kay Ayeni, Warren Bain, Chris Baker, David Baxter, Graeme Beale, Nick Beere, Derek Bell, Adam Benwell, Divya Beta, Paul Bigland, Luke Binner, Chris Bond, Matt Bowey, James Brandon, David Brignall, Gary Bromley, Paul A Brommer, Chris Bryan, Richard Bunning, David Burgess, Viv Burke, Dan Burrows, Benn Burton, Peter Byrne, Douglas Carpenter, Christine Caulfield, Iain Chalker, Thom Chapman, Michael Cheetham, Laura Chester, Constantin Ciobanu, Ross Clark, Jeremy Claxton, Chris Cockram, Piers Connor, Jordan Cooper, Kevin Cooper, Alex Corcoran, Russ Cordingley, Eddie Cowens, Richard Crabtree, Thomas Crame, Paul Croft, Gary Crutchley, Matt Curtis, Tom David, Mark Davies, Mark Davis, John Day, Gareth Dennis, Ian Derbyshire, Catia Dias, Noel Dolphin, Mark Dowding, Stephen Draycott, James Drury, Owen Dunn, Bradley Dzimba, Ian Edwards, Richard Ellerton, Mark Elliott, Leon Ellis, John Evans, John H Ewing, Richard Fargher, Mark Ferguson, Ian Ferrier, Jack Fisher, Mark J Foley, Neil Fowler, Andrew Gardner, Alex Geary, Mark George, James Giddings, Matt Gilluley, Rupert Goffe, Tommy Gore, Logan Govender, Cosmo Graham, Andy Gray, Neil Grennan-Heaven, Ana Halangau, Mark Hallett, Geoff Hancox, Daniel Hanvey, Jack Hardington, Kieran Harrop, Leigh Harvey, Hamish Harvey, George Hayllar, Terry Haywood, Jamie Heaton, Peter Herridge, Charles Heseltine, Alan Hetherington, Ray Hirtsch, Edward Holman, Ben Hopkins, David Horne, Graham A Howarth, Ben Hunter, Simon Iwnicki, Russell Jackson, Gordon Jahn, Tim Jarvis, James Jefferies, Gordon Jilks, Abi Johnson, Colin Johnson, Steven Johnson, Robert Jones, Ashley Jordan, Sonny Kanganga, Stuart Kelly, Alan Kennedy, Mohammad Munir Azam Khan, Matt Kirkham, Paul Knight, Tom Lane, Edward Lennard, Ashley Lovell, Paul Lundy, Anne Maningas, David March, Russ Marris, Chris Marsh, Dr Brian Marshall, Simon A.C. Martin, Faye McCarthy, Robert McClelland, David McCormick, Adam McCreadie, Stuart McGowne, Alan Mclauchlan, Edward Mellor, Lucy Millard, Richard Miller, Ian Moore, Tyson Moore, Scott Morris, Alexander Morton, David Mulligan, Lewis Nagle, Adam Norton, Alan O’Hara, Martin O’Connor, John O’Dea, Katen Oza, Annie Evangaline Parayakattil, Asad Parkar, Jonathan Parker, Matty Parkin, Andrew Paton, Matthew Peers, Jack Pendle, Joe Percy, Russell Peterson, Giles Pettit, Pfisterer Ltd, Danny Platt, Adrian Podmore, Driver Potter, David Preston, Cloe Raan, Anesh Ramkhelawon, Moises Ramos, William Robinson, Jordan Rolfe, Richard Ryan, Stewart Saxton, Peter Savage, Martin Savage, Ryan Searle, Eiki Sekine, Jo Sharpe, Gary Shenton, Steven Shiel, Sanchay Singhal, Bradley Skelley, Simon Skinner, Gavin Smith, Jason Smith, Richard Sobutta, Dave Speakman, Jamie Stallwood, Martin Stephenson, Graham Stubbings, Mark Sullivan, Ben Talman, Taku Tamaki, Chu Xuan Tay, Darren Taylor, Brett Tharp, Mark Thomas, Christian Thompson, Lachie Tod, Martin Treacy, Graham Troupe, Marcin Tryszcz, David Vamplew, Davey Waddington, Simon Wadsworth, Simon Jam Wall, Keith Waller, Johannes Wallisch, Paul Walker, Sean Walsh, Simon Warren, Hannah Watchman, Andrew Westwood, Anthony Whiteford, Keith Whoriskey, Robert Wilkins, David Willcock, John Williams, Adrian Williams, Ken Willy, Chris Wilson, David Wilson, Paul Wilson, Stuart Witts, Martin Woodcock, Shaun Woods, Andrew Worstencroft, Brian Wortman, John Wright, Christopher Wright.

Current Errata List

This is the list of errors which exist in the hardback printed 6th edition.

Page 6, figure 3 was taken at Bow Junction, not Bethnal Green.

This is the list of errors which exist in the free PDF download 6th edition.

Page 6, figure 3 was taken at Bow Junction, not Bethnal Green.

Page 58, figure 62 – touch potentials are shown at the top of the diagram, and step potentials below; not the other way around as suggested by the caption.

Page 59, figure 65 – the signalling rail is labelled incorrectly. The correct diagram is below:

Page 117 should read:
these systems use a triple cantilever… on the same principle as the double cantilever. The double cantilever illustrates the important principle…”

Page 162 should read:
“…where a resistance is switched into the OLE circuit…”

Page 234 should read:
“This section focuses on the general principles…”

This is the list of errors in the hardback printed 5th edition.

Page 45, figure 28 – this circuit breaker uses Nitrogen, not SF6 as an insulating medium.

Page 46, figure 30 – this cable is not armoured. The outer layer of copper is a sheath, not armour.

Page 58 states that “MSCs in the UK are typically PVC sheathed 19/4.22 Aluminium cable…”. In fact it is typically 19/4.22 cable.

Page 63: “Similarly, circuit breaker C A will act if circuit breaker B does not.”

Page 80, sentence should read:
“This is because DC stray currents can be especially damaging to the running rails…”

Page 91, sentence should read:
“The key interface to be considered in OLE design is that of the contact wire…”

Page 91, figure 84 – label “raising cylinder and primary insulation” should read “raising cylinder and primary suspension”

Page 149, sentence should read:
“A variant of this design, used for more highly loaded masts…”

Page 171, figure 200 was taken at St Pancras, not Kings Cross

Page 176 states that “19/3.25 Al (with a PVC sheath) is also used for MSCs and RSCs…”. In fact it is 19/4.22 cable that is used. Figure 207 also erroneously references 19/3.25 cable as RSC.

Page 178, sentence should read:
“These comprise a very large number of small diameter strands – usually copper – which are woven into ropes…”

Page 216: 31 people died in the accident at Ladbroke Grove, not 30 as stated.

Page 235, sentence should read:
“Measurements taken during these tests include rise in earth potential, feeder current, fault clearance tomes times and return current paths…”

Appendix D:
Series 1 equipment is listed as using Copper Tin (CuSn) contact wire. In fact it uses Copper Silver (CuAg) contact wire.

Looking for great OLE images

One of the things that we put a lot of effort into is getting the best possible images for the book. For the upcoming 6th edition we have a large number of new and original photos – but there are still a few items that are eluding us; usually for geographical reasons or because the equipment is not accessible to the average div with a camera (me).

If you are reading this and can help with any of these, please get in touch. Please bear in mind that we can only accept images that are high quality (sharp, good exposure) and crucially, that are your copyright. Please don’t suggest images that you got from a 3rd party or website.

These are the images we’re looking for:

  • Three wire crossover
  • Side wear of contact wire
  • Oil Circuit Breaker
  • Vacuum SMOS circuit breaker
  • SF6 indoor circuit breaker
  • 132kV or 400kV feeder station supply transformer
  • AC protection relay
  • SCADA outstation
  • Long portable earth + clamp
  • Panning of OLE
  • Mineral hopper under OLE
  • Contact wire chopping device at Frankfurt tunnel flood doors
  • Panchex uplift monitoring
  • Balance weights in tunnel
  • Burndy tool