Signal Trunking Placement Advice

[The Black Hat]

Hello all,

 

To get more realism onto the layout Im looking to add detail, such as signalling trunking and piping to points and signals. On the layout is a signal box controlling the station, and would be staffed by Network Rail, given its the transfer point to a preserved railway. Although the preserved engines run in, Im thinking all would have TPWS fitted as a minimum, akin to Whitby operation as the branch is still 12 miles away from the mainline propper at Darlington.

 

In order for the signals to be controlled I would expect wires to be placed. This would need signalling trunking to run the length of the layout, with wires and piping then moving from this to the various signals and point motors. Given all are colour light and point motors are to be added that makes a fair bit of control needed. Also, TPWS grids need to be fitted to the layout.

 

I am wondering where the permament way would put the signalling cabling. Past experience tends to suggest that this would be to the sides of the tracks, but in this station the platforms are there. So would it just run underneath the platform edge (along the green line on the map shown below), or would it be put through the centre and closer to the Network rail side of operation (ie where the blue line runs instead).

 

 

Thanks in advance for any advice given.

[Chameleon]

Generally I've seen the cables mounted along the side of the platform, either on hooks or brackets at regular intervals. Often stacked up on top of each other if there are a lot of them. Once at the end of the platform, they would return to the concrete trunking. Also, if cables cross under the tracks, they are usually fed through red or orange plastic tubing mounted flush with the surface of the ballast to protect them.

[TheSignalEngineer]

The permanent way don't do signalling cables. They only destroy them with tampers etc.

 

Some basics to start off with.

• Don't put main cable routes under points.
• Don't put main cable routes behind stop blocks.
• Do try to put main cable routes where they can be worked on safely without a possession.
• For main cable routes under tracks use buried pipe crossings with manholes at each side.
• In case of not being able to get a route anywhere else through the station, tie the cables to admiralty tray on the platform wall.

[The Black Hat]

Okay. Well sorry to all the signallers out there for the generalisation on permament way.

 

Im thinking, given the advice that the route I've highlighted in yellow in the old pic of the layout below would be where is best to send the cables. I was aware of keeping the main parts clear of points etc,

 

 

 

Can I also ask - would you have additional relay boxes near the points and signals at the far end of the station. Im guessing you would, as controls would go there from the box (down one larger control cable) and then to the point or signal in question. 

 

Thanks again...

 

[phil-b259]

In the case of platforms, one often used method is to dig up the platform surface and bury the cable route within (with regular inspection chambers to facilitate cable installation / repairs). It also makes it easier for said cables to call in to any location cases installed on or behind the platforms themselves.

 

You also have to consider things like what circuits the cables actually carry - For example the tail cables to individual pieces of equipment will require less protection than big 48 core cables carrying multiple functions - damage to which could affect a wide area.

 

Installing lots of cabling to the platform wall is frowned upon these days as it impinges on the "survival space" all platforms are supposed to provide these days, plus doing ANY work on it - even running new cables will require line blockages (Techs are forbidden from working on the railway between station platforms these days as there is no place of safety available unless a line is blocked - heaving yourself back on the platform doesn't count).

 

Installation practices may also be influenced by whether it is basically a mechanically signalled layout with various bits of equipment converted gradually over the decades to power operation, or whether a specific resignalling scheme has been carried out. In the former cases things like cable runs could be a bit all over the place, but if it is a proper scheme (which can be very small or very big in scope by the way) then one of the first tasks will be to devise a proper cable route through the site upon which all the location cases can be "hung"

[phil-b259]

Can I also ask - would you have additional relay boxes near the points and signals at the far end of the station. Im guessing you would, as controls would go there from the box (down one larger control cable) and then to the point or signal in question. 

.

 

Definitely

 

You need to consider things like volt drop, current draw, etc when planning feeding arrangements for any piece of kit so the most common setup will be for the circuits controlling point operation to be fed from and reporting back to location cases adjacent to the pointwork, with repeater circuits carrying the commands to move from the box and other repeater circuits carrying the detection indications back.

 

Similarly track circuits will have the actual relay operated by that track in a location case close to where the track circuit finishes, with repeater circuits used to report the status of the track circuit relay back to the box, or to hold automatic signals at red etc.

[The Black Hat]

Right, so putting it along the platform isnt an option. Im wanting it to be accurate as according to my railways developments all of this will have happened between the last 10 years or so.

 

If thats the case, would it be easier to run it all on the side with the Network rail platform. It would cross to the box where the single line is straight, near the box on the diagram and just off picture on the photo. Im guessing then I can put it along that side and then cross it before the loading area. Its all possible to do.

 

As a result Im wondering about location cases. So tell me if I have this right, but from each location box I need wires to:

 

1. Every signal

2. Every track circuit

3. Every point motor

4. Every TPWS grid.

 

If thats the case, my layout is about to get a load more wiring done.

[The Black Hat]

Also just wondering how might the signalling cable swtich from one side of a main line to the other. Just using the orange piping or something more robust?

[TheSignalEngineer]

The main route would usually cross in a buried pipe crossing. Subsidiary cables would depend on the fashion at the time and in the area concerned. Sometimes it would be orange pipe, others the cables were cleated to sleepers. Going back a while it would be timber boxing and sometimes small concrete troughing.

 

As always installation date and controlling organisation are key to what would be done.

[big jim]

<p> The permanent way don't do signalling cables. They only destroy them with tampers etc.

 

That made me chuckle!!

[phil-b259]

Also just wondering how might the signalling cable swtich from one side of a main line to the other. Just using the orange piping or something more robust?

Surfacing running almost invites cable damage from P- way activities, plus every time the railway wishes to remove ballast and sleepers etc the cables need to be removed. If this involves disconnecting ANY circuits, then FULL TESTING of EVERY cuit is required before the relevant equipment can be returned to service.

 

Tail cables (which only carry circuits for indavidual bits of equipment) can be surface run partly because there can sometimes be no other way, but also because if they are damaged the effects will be contained. Testing of one piece of equipment / circuit is not too bad - testing of a 48 core cable on the other hand is a very different proposition.

[The Black Hat]

 

Some basics to start off with.

• Don't put main cable routes under points.
• Don't put main cable routes behind stop blocks.
• Do try to put main cable routes where they can be worked on safely without a possession.
• For main cable routes under tracks use buried pipe crossings with manholes at each side.
• In case of not being able to get a route anywhere else through the station, tie the cables to admiralty tray on the platform wall.

 

 

 

Surfacing running almost invites cable damage from P- way activities, plus every time the railway wishes to remove ballast and sleepers etc the cables need to be removed. If this involves disconnecting ANY circuits, then FULL TESTING of EVERY cuit is required before the relevant equipment can be returned to service.

 

Tail cables (which only carry circuits for indavidual bits of equipment) can be surface run partly because there can sometimes be no other way, but also because if they are damaged the effects will be contained. Testing of one piece of equipment / circuit is not too bad - testing of a 48 core cable on the other hand is a very different proposition.

 

Being in the area I called into Darlington station to see close up some of the way in which the signalling equipment, points etc are all wired up and working. Oddly enough, I did find one area with point rodding that controls access to the engineers siding.

 

I noticed that all the TPWS grids are wired up, that they come from trunking cable routes alongside the station walls. Any signals, such as those controlling the bays and the derailers on the approach all are wired up with the cables indeed going under routes that can be seen with man hole covers. There is still AWS in the station, although Im not sure if this would be redundant given TPWS is there. It means Im more sure of the way in which I need to get the wiring seen on the surface from the individual location cases to things like points, signals etc.

 

So, Id like to check the following. Would location cases house multiple equipment, such as signals, point etc, all in one area, or would it be seperate. If seperate, how many signals (for example) would you have generally controlled from one location case? Also does the distance between a TPWS grid and the signal it protects, change due to linespeed - as Im wondering how far apart to place grids protecting signals in the station.

 

Thanks again. Its all been useful and informative.

[TheSignalEngineer]

So, Id like to check the following. Would location cases house multiple equipment, such as signals, point etc, all in one area, or would it be seperate. If seperate, how many signals (for example) would you have generally controlled from one location case? Also does the distance between a TPWS grid and the signal it protects, change due to linespeed - as Im wondering how far apart to place grids protecting signals in the station.

 

Thanks again. Its all been useful and informative.

Equipment would be grouped together and fed from one or more cases at a particular location. TPWS does not replace AWS, it serves a different function.

 

Standards for current work and a lot of old documents are available on line from the Railway Group Standards website. Start at this page http://www.rgsonline.co.uk/Pages/advancedsearch.aspx and use the word search option to pull up all documents mentioning a particular thing.