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· Registered
4,548 Posts
This Sub-forum has been set up to co-ordinate information on signalling, both modelling and prototype. There was much useful information on the subject scattered about the Forum, but it was difficult to locate - a search for 'signals' bought in about three times as much on DCC signals rather than on railway Signals. So Doug was kind enough to set up this sub-forum at my suggestion. I gave him details of the various threads I thought appropriate to include. If there are any more you think worth moving into this sub-forum, please either post a link here or send Doug the topic reference number.

John Webb

PS - I've reached 'Engine Driver' with this post!

· Chief mouser
11,779 Posts
QUOTE (John Webb @ 1 May 2007, 11:36) <{POST_SNAPBACK}>PS - I've reached 'Engine Driver' with this post!

Congratulations on your passing out.

Seriously I will see what books/articles etc. I have on the subject and post a list.



· Administrator
10,720 Posts
Great idea John and thanks to Doug for moving job


· Registered
2,681 Posts
Experience has taught me to try to closely define which railway company or consecutive companies have been reponsible for the signalling in the area I am looking at. It can also be useful to check out which signal manufactureres were used at various times. All of this is of course directly affected by the date/period in which I have an interest.

From 1889 it can be pretty much assumed that any passenger carrying railway in the UK will have been operated using Absolute Block Working Regulations whether these are applied to a single or double lines. (Multiple Lines just keep adding to the double line system). It is therefore useful for an enthusiast to gain a basic knowledge of Absolute Block Working. A Copy of Signalman's Regulations of almsot any railway company for the period chosen would be a good starting point - any company because there are only pretty minor variations between how the different companies did it for the basic system. A BR Sig's Regs would serve most people's purposes.

It would be possible to move on from Absolute Block to Intermediate and Automatic Block from Sig's Regs. If wanted non-passeneger lines could be worked using Permissive Block Regs.

For Layouts wanting to use Multiple Aspect Colour Light Signalling - which is worked under Track Circuit Block Regulations - the same BR Sigs Regs will provide the Regulations (TCB).

TCB is basically the same whatever kind of colour light signals are used and for both track circuit and axle counter equipt lines.

It is much easier to work out the signalling for Pre TCB signalling arrangements. There is more published information that is accessible to non-professionals plus it is much easier to see what was there and fit it to the logic of the system than is the case with TCB arrangements. The earlier TCB layouts are, however, much easier to follow due to the fact that the thinking was still largely based on Absolute Block Working. (This is assuming that you don't look at the Mirfield scheme on the LMS or London Underground).

One thing to get clear in the mind is that UK systems are "Space Interval" systems. If this can be recognised everything rapidly becomes more simple to comprehend.

For reference the other ways of working are Time Interval (Which can include Timetable and Train Order systems) and "Speed Signalling". I wouldn't go there unless it was really necessary.

The great thing about Space Interval systems is that the track is divided up into chunks - spaces - Whatever sources you find this will virtually always apply in the UK.

There are two initial chunks of line. Those equipt for trains carrying passengers and those that are not. The two are always segregated from each other. To get from a non-passeneger [carrying] line of any kind to a passenger [carrying] line a movement will always have to proceed over a Trap Point (also known as a Catch Point) or (much less commonly) past a derail device.

Once we are out onto Passenger carrying lines we will be into Absolute territory. Absolute Block, Intermediate Block, Automatic Block and Track Circuit Block are all "Absolute " systems. In Normal Working in an absolute system only one train in one direction is allowed in any one length of line between consecutive Stop Signals at any one time. How you get trains coupled or uncoupled is a seperate subject.

Absolute territory is divided into Signal Sections. A Signal Section is the length of line between Fixed Stop Signals.

In Absolute Block the line between the last Stop Signal of one signalbox/Block Post to the first Stop Signal of the next signalbox/Block Post is the Absolute Block Section. The line between the first Stop Signal of one signalbox/Block Post to the last Stop Signal of the same signalbox/Block Post is the Station Limits of that signalbox/Block Post.

I'm going to skip over Intermediate and Automatic Block.

TCB has Signal Sections between consecutive Stop Signals. If you think that this would make life easier you would be misled.

Right. Having said all that the point I am getting round to is that almost any book with pictures of UK railways will give you information about UK signalling practice.

If nothing else you can look at what the signals looked like and where they are. This isn't as daft as it sounds. The better picture you can have in your head of what signals look like and where they are the easier it is to put the signals together with the method of working - AB or TCB.

I will relate it to learning to drive. If one were to go out onto the roads with no concept of driving on the left, what signs and road markings looked like it would be far harder to take what is going on on board at the same time as trying to drive. In the same way getting an idea of what different types of signals do, what they look like and where they are placed makes understanding what needs to be learnt far easier.

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