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I was wondering if anyone knows where I can access a comprehensive guide on how interlocking works and its design? Ideally with diagrams etc. I am a signaller so understand what interlocking does and why it's there and understand the principles etc. I'm just interested if there is a rulebook/document that really breaks down all the different types of interlocking and how they work? I can't seem to find one. I found this document:
Requirements for Passenger Lines and Recommendations for Goods Lines
which is the type of thing I'm looking for but it is very old (published 1950s) so I'm looking for the modern version of this. Preferably the most up to date one.
A lot of this has now been broken up into the various NR and RSSB Group Standards. As you're a signaller, it might be worth asking your Ops Managers if they can ask signalling engineers about this?
Are you looking for something at the sort of 'Mechanical vs Relay vs SSI vs Computerised RBC' level or are you looking for a proper breakdown of each manufacturer's systems?
A lot of this has now been broken up into the various NR and RSSB Group Standards. As you're a signaller, it might be worth asking your Ops Managers if they can ask signalling engineers about this?
Are you looking for something at the sort of 'Mechanical vs Relay vs SSI vs Computerised RBC' level or are you looking for a proper breakdown of each manufacturer's systems?
Mechanical vs relay etc would be interesting. But really I'm just looking for a document which states the "rules" on designing an interlocking system, explaining all situations where locking is required. For example, a set of points must be locked if you have cleared the protecting signal, and the home, section, distant sequence etc.
Maybe such a document does not actually exist haha
Mechanical vs relay etc would be interesting. But really I'm just looking for a document which states the "rules" on designing an interlocking system, explaining all situations where locking is required. For example, a set of points must be locked if you have cleared the protecting signal, and the home, section, distant sequence etc.
Maybe such a document does not actually exist haha
Those rules will be covered by a mix of RSSB and NR standards. I suspect there'll be multiple documents to cover the entire area you're interested in, but this looks like a start: https://www.rssb.co.uk/standards-catalogue/CatalogueItem/GKRT0055-Iss-1 (you can register with a NR email address).
Those rules will be covered by a mix of RSSB and NR standards. I suspect there'll be multiple documents to cover the entire area you're interested in, but this looks like a start: https://www.rssb.co.uk/standards-catalogue/CatalogueItem/GKRT0055-Iss-1 (you can register with a NR email address).
The Dickthesignals website (https://dickthesignals.co.uk/) has a plethora of. documents detailing signalling scheme design, regulations and training documents. If you go into "Heritage Signalling Information" and then "BRB Training Manual" there are some quite thorough explanations. Mechanical interlocking one is quite detailed on what points need locked since you mentioned that above - https://dickthesignals.co.uk/onewebmedia/22 mechanical interlocking.pdf.
The RSSB's standard catalouge, as others have mentioned, has some explanations. I'd search for "SSP" which are the now archived British Rail Standard Signalling Principles. They cover everything from the provision of co-acting signals to overlaps and trap points! I believe it goes into some level of interlocking (e.g. control tables for bay platform signalling in SSP033.) Alot of these are still in use but are now internal network rail documents or have been amalgamated into other standards.
Quickly, the general term you need to search for "rules" of interlocking (and the rest) is principles.
Your QUOTE For example, a set of points must be locked if you have cleared the protecting signal, and the home, section, distant sequence etc. UNQUOTE comes under principles.
Search for "signals (or signalling) principles".
I have done, a good while ago now, an LU signals principles course that covers all that sort of thing; actually never needed to use it for my job it was more of a core learning thing for command and control systems. LU and main line principles are not equal e.g. trainstops, signal sequences, track circuit location, even LU points locking principles are not equal.
EDIT
The 'de facto' reference books to seek out are the IRSE so called "Green Books"; these appeared in 1960/1970s and not (that I know of) updated since but remain THE standard main line principles works. They are series of about two dozen (?) in all and are modularised by subject.
IMHO read these before you attempt to read current industry standards. IME unless you are actually working in a specifc area 'standards' documents offer little help and much bafflement. Need to understand the underlying principles first, which is exactly why 'signalling principles' are so named, and exactly what the IRSE Green Books are intended for. Indeed standards will be for those who are already knowledgable and qualified in the area they apply to, they are hardly learning documents.
Pretty sure Green Books long out of print, but can be found 2n hand; also I /think/ not sure IRSE themselves may have them available in PDF form, but you might have to be a IRSE member to get these.
As you work in the rail industry, it is possible your employer has a professional institution bulk membership scheme where you can get a free membership of certain institutions but only at the lowest level e.g. associate. No idea if IRSE are in such a scheme (IRO certainly is); the point of mentioning it is free membership might give you access to free documents ? Just a suggestion.
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The list :
Institution of Railway Signal Engineers (IRSE)
Educational Lecture Series (“The Green Books”)
1. Principles of the Layout of Signals
Author: W H Challis.
Publisher: IRSE 1960.
Chapters on Mechanical Signalling, Colour light Signalling, Signalling as an Aid to Increased line Capacity.
2. Principles of Interlocking
Author: W H Such.
Publisher: IRSE 1949, 1963.
3. Mechanical and Electrical Interlocking
Author: W H Such.
Publisher: IRSE 1949, 1963.
4. Single line Control
Author: P C Doswell.
Publisher: IRSE 1950, 1957.
5. Principles of Power Point Control and Detection
Author: H W Hadaway.
Publisher: IRSE 1950.
6. Signalling Relays
Author: J F H Tyler B.Sc.(Eng).
Publisher: IRSE 1951, 1958.
7. Signal Control Circuits
Author: J P Loosemore.
Publisher: IRSE 1951, 1958.
8. Typical Selection Circuits
Author: J P Loosemore.
Publisher: IRSE 1951, 1968.
9. Track Circuits
Author: W H Challis.
Publisher: IRSE 1951.
10. Mechanical Signalling Equipment
Author: Donald L Champion.
Publisher: IRSE 1952, 1957.
11. Railway Signalling Power Supplies
Author: D L Mitchell.
Publisher: IRSE 1952, 1958.
12. Block Instruments
Author: J H Currey.
Publisher: IRSE 1952, 1958.
13. Train Describers
Author: J E Mott.
Publisher: IRSE 1952, 1958.
15. Circuits for Colour light Signalling
Author: J Hawkes.
Publisher: IRSE 1969.
16. Holding the Route
Author: W H Challis.
Publisher: IRSE 1964.
17. Track and lineside Signalling Circuits in AC Electrified Areas
Author: J E Candler, G I Foster, W M Sweetenham.
Publisher: IRSE 1962.
18. Principles of Relay Interlocking and Control Panels
Author: N Marshall.
Publisher: IRSE 1961.
20. Route Control Systems (W. B. & S. Co.)
Author: J E Hawkes.
Publisher: IRSE 1961.
22. Route Control Systems: The S.G.E 1958 Route Relay Interlocking System
I think the kind of document that you are after is NR's Signalling Principles and Application Handbook NR/L2/SIG/30009. This was intended to mop up all the individual instructions into one handbook, but the last I saw still had vast parts as To follow or Not Yet Issued (e.g. the complete section on Mechanical Signalling). Until they do get mopped up, many of the individual instructions still exist as GK/RT series instructions.
The IRSE green books are very much out of date, and mainly describe 1950s and earlier technology, although I think they did do a grey book on SSI? However, of much more relevance are the IRSE text books Railway Signalling and its sequel Railway Control Systems. Published by A&C Black, you should be able to borrow copies from your library, using the inter library service if necessary. The first one may have OS Noch as the editor, the second Maurice Leach, if needed for searching. However, be warned that the green books and the text books rapidly get very technical.
The IRSE green books are very much out of date, and mainly describe 1950s and earlier technology, although I think they did do a grey book on SSI? However, of much more relevance are the IRSE text books Railway Signalling and its sequel Railway Control Systems. Published by A&C Black, you should be able to borrow copies from your library, using the inter library service if necessary. The first one may have OS Noch as the editor, the second Maurice Leach, if needed for searching. However, be warned that the green books and the text books rapidly get very technical.
Anything with Nock as editor is almost as out of date in terms of technical advances considering he passed away 30 years ago.
I suggest the Green Books are only out of date w.r.t. new installations control - but entirely relevant trackside to vast amount of legacy equipment out there, contemporary or earlier. Only when you get into non track circuited but axle counted lines, ETCS, etc, do they cease to be of mainstream.
If you take a modern pc work station control centre - but out on the ground is a multiple aspect track circuited relay interlocked railway then the Green Books do apply. Read SSI vice relay, the principles laid out in the Green Books still apply.
e.g. West Hampstead power box the NX panel replaced 12/2023 by workstations but it is still 1970s technology 1980s installed signalling on the ground. The 4 aspect MAS works here exactly how the relevant Green Book explains it.
The OP said QUOTE a comprehensive guide on how interlocking works and its design? Ideally with diagrams etc. I am a signaller so understand what interlocking does and why it's there and understand the principles etc. UNQUOTE the Green Books do that.
The OP membership info says from Dundee; lets make an assumption, signaller in Dundee box maybe ???? I bet (without knowledge) that entire Dundee area is relay or SSI interlocking - and SSI interlocking does its interlocking by exactly the same rules (principles) as relay interlocking.
Anyway, mechanical or electrical or relay or SSI or CBI interlocking, from the PRINCIPLES point of view are all the same. They do the same thing under the same configuration rules. Overlaps, flank protection, interlocking, sequencing, all the same. It is only how they do it that is different. So need to get the underlying principles first before going into the detail of how it is carried out in successive technical generations.
Using foreign sources is risky. Signalling is a field where there isn't much in the way of comparisons between different countries, as well as a lot of cases of people taking what's the case in other countries as universally applicable.
The Dickthesignals website (https://dickthesignals.co.uk/) has a plethora of. documents detailing signalling scheme design, regulations and training documents. If you go into "Heritage Signalling Information" and then "BRB Training Manual" there are some quite thorough explanations. Mechanical interlocking one is quite detailed on what points need locked since you mentioned that above - https://dickthesignals.co.uk/onewebmedia/22 mechanical interlocking.pdf.
The RSSB's standard catalouge, as others have mentioned, has some explanations. I'd search for "SSP" which are the now archived British Rail Standard Signalling Principles. They cover everything from the provision of co-acting signals to overlaps and trap points! I believe it goes into some level of interlocking (e.g. control tables for bay platform signalling in SSP033.) Alot of these are still in use but are now internal network rail documents or have been amalgamated into other standards.
......e.g. West Hampstead power box the NX panel replaced 12/2023 by workstations but it is still 1970s technology 1980s installed signalling on the ground. The 4 aspect MAS works here exactly how the relevant Green Book explains it......
Minor correction - most signal heads in the area West Hampstead covers were replaced in the last couple of decades by LED heads. NR were kind enough to let us at St Albans South have half-a-dozen of the old heads to make up demonstrations of MAS signalling....
Minor correction - most signal heads in the area West Hampstead covers were replaced in the last couple of decades by LED heads. NR were kind enough to let us at St Albans South have half-a-dozen of the old heads to make up demonstrations of MAS signalling....
none of which alters the principles by which the four aspects come to be displayed
what drives the 4 different aspects of LED lamp heads and why they display what they do when they do is exactly the same as what drives the 4 different aspects of separate filament bulb heads and why they display what they do when they do
they could be LNER / BR ER type 4 aspect searchlight signals - but why they display when they do R Y YY G is the same principle
that is what signals principles is - not the detail of how it is done
LEDs in railway signalling applications were impractical when the IRSE Green Books were compiled (possibly not even invented when the relevant book was) but the principle behind 4 aspect track circuited MAS applied then and the explanation applies today
that is why the IRSE Green Books are important reading
Fair comment! I got a number of the 'Green Books' when I first became involved in setting things up at St Albans South, although as we're non-safety critical, we can use simpler and less complex circuits. It's really the safety-critical principles that are important and the Green Books do provide a good background to this need, however in the end it is carried out.
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