Signals with Triangles

[Peter0124]

Hello, does anyone know what the triangle means on certain signals? Eg between Blantyre and Newton there is a signal which has a white triangle above the 'GMN201' tag. There is no signal berth for it on railcam diagrams or traksy. I believe there is also one between Hamilton West and Blantyre. Does anyone know what its purpose is and why there is no berth for it on the signalling map (railcam/traksy)? I don't have a photo but if I manage to get one while passing by on a train I will send it over. Thanks!

 

[RightAwayGuy]

It's a distant signal.

 

[hexagon789]

Hello, does anyone know what the triangle means on certain signals? Eg between Blantyre and Newton there is a signal which has a white triangle below the 'GMN201' tag. There is no signal berth for it on railcam diagrams or traksy. I believe there is also one between Hamilton West and Blantyre. Does anyone know what its purpose is and why there is no berth for it on the signalling map (railcam/traksy)? I don't have a photo but if I manage to get one while passing by on a train I will send it over. Thanks!

There's one at Whitecraigs, with a white triangle and it denotes a distant signal - ie not capable of displaying a red aspect.

 

[CAF397]

The signal is a Distant signal

 

[_toommm_]

If you mean like the example shown on signal CE310 on this page, then it indicates that it is a distant signal:

Signal Post Signs and Signals for Degraded Working

 

[Railsigns]

The double delta plate to identify outer distant signals (most restrictive aspect double yellow) is on trial today.

 

[Annetts key]

Hello, does anyone know what the triangle means on certain signals? Eg between Blantyre and Newton there is a signal which has a white triangle below the 'GMN201' tag. There is no signal berth for it on railcam diagrams or traksy. I believe there is also one between Hamilton West and Blantyre. Does anyone know what its purpose is and why there is no berth for it on the signalling map (railcam/traksy)? I don't have a photo but if I manage to get one while passing by on a train I will send it over. Thanks!

Distant or ‘colour light repeater’ signals are not ‘block’ signals, hence will not have a train describer berth. There may also not be a separate track circuit / axle counter section for them.

They are very common where two aspect signalling is used. And occasionally are found as three aspect (yellow, double yellow and green capable heads) to act as a distant signal for a four aspect signal where there is a long section, or for performance/capacity reasons (on the approach to a busy section of track such as a station or junction where trains are slowing and bunching up).

 

[Peter0124]

Found it! There is also one between Hamilton Central and Hamilton West aswell.

 

[skyhigh]

There is also one between Hamilton Central and Hamilton West aswell.

There are loads of them about the network.

 

[Annetts key]

Found it!

Yep, distant signal.

 

[Peter0124]

So basically are they just there to tell the driver that the next signal is at danger / is green?

 

[Annetts key]

So basically are they just there to tell the driver that the next signal is at danger / is green?

They exist to provide a driver with enough information so that the driver can correctly control the speed of their train on the approach to the next signal (or where capable of a double yellow) the next but one signal.

Or more technically, they provide the train driver with sufficient warning such that there is service braking distance to the end of authority (the red ‘stop’ signal) when they display a caution (yellow) or preliminary caution (double yellow).

 

[FS-2-11]

Found it! There is also one between Hamilton Central and Hamilton West aswell.

It looks odd with yellow-over-green. Am I right in believing that it's usually preferable to have the more restrictive aspect closer to the driver's eye line?
Maybe there's an exception in this case e.g. sighting considerations where it's preferable to have the yellow aspect higher up.

 

[Railsigns]

It looks odd with yellow-over-green. Am I right in believing that it's usually preferable to have the more restrictive aspect closer to the driver's eye line?

GMN201 is a three-aspect distant signal with three lenses in the order yellow-green-yellow. Single yellow is displayed in the bottom lens unit.

 

[Annetts key]

GMN201 is a three-aspect distant signal with three lenses in the order yellow-green-yellow. Single yellow is displayed in the bottom lens unit.

Yes, so the available aspects are:

• single yellow (the signal ahead is currently showing red)
• double yellow (the signal ahead is currently showing single yellow)
• green (the signal ahead is currently showing double yellow or green)

 

[Dougman]

Is there not a difference between a distant signal and a repeater signal? The repeater indicates the state of the next signal but a distant indicates that all signals controlled by that box are clear (and also that a yellow distant followed by a green signal means the next signal after the green might be at red)?

In fact I think there was SPAD at Carnoustie years ago caused by that misunderstanding, driver has yellow on the distant, home stepped from red - green on his approach so he accelerated but the section signal was still at red.

 

[High Dyke]

Is there not a difference between a distant signal and a repeater signal? The repeater indicates the state of the next signal but a distant indicates that all signals controlled by that box are clear (and also that a yellow distant followed by a green signal means the next signal after the green might be at red)?

In fact I think there was SPAD at Carnoustie years ago caused by that misunderstanding, driver has yellow on the distant, home stepped from red - green on his approach so he accelerated but the section signal was still at red.

I'm not sure about definition, but the location I'm at this morning has Up Main distant, Up Main Home and Up Main starter. The up Main Distant is identified as 1R, it's part of the 3-aspect starter signal at the adjacent signal box. The up home is accordingly #1 and the Starter #2.

The rule book is quite clear about clearance of a stop signal when the next signal is at red. I work a couple of locations where that is used. If you don't follow that procedure correctly, then you are now enticing drivers into a SPAD trap. That happened at Barkston East on the last day of operation, and the signaller on duty was dismissed as a result.

 

[Railsigns]

Is there not a difference between a distant signal and a repeater signal? The repeater indicates the state of the next signal but a distant indicates that all signals controlled by that box are clear (and also that a yellow distant followed by a green signal means the next signal after the green might be at red)?

No, not in current usage. A distant signal is any signal that displays a caution aspect but not a stop aspect. GK/GN0802 "Glossary of Signalling Terms" says "repeater signal" is a non-preferred term for a distant signal.

 

[Tempest Malice]

Is there not a difference between a distant signal and a repeater signal? The repeater indicates the state of the next signal but a distant indicates that all signals controlled by that box are clear (and also that a yellow distant followed by a green signal means the next signal after the green might be at red)?

So what you have given is the common enthusiast definition for these things (and I think some drivers still think in these terms too).
But to modern signalling engineering standards there is no such thing as a "repeater" signal (except a "banner repeater", which is it's own quite separate thing), and "distant" as a term covers all signals which can't show red.

The difference you are trying to describe is in signalling engineering terms instead given by whether it is a "multiple aspect" or "semaphore" distant. Though, those words only refer to the operational meaning of the signal and not the technology of construction which are instead described by the terms "mechanical" and "colour light" in the signalling principles. I.E. you can have a "colour light semaphore distant" (what you call a distant) and a "multiple aspect colour light distant" (what you want to call a repeater) Both of these would have the triangle on their ID plate (known as a delta plate to those that invented the thing and called that by approximately nobody else) to show they can't show a red if they were designed to the most recent standards. Though to save confusion thankfully very few semaphore areas are likely to be resignalled to get such without being completely replaced.

 

[zwk500]

So what you have given is the common enthusiast definition for these things (and I think some drivers still think in these terms too).
But to modern signalling engineering standards there is no such thing as a "repeater" signal (except a "banner repeater", which is it's own quite separate thing), and "distant" as a term covers all signals which can't show red.

Was there not a bit of confusion also caused by the use of the 'R' Suffix?

 

[Tempest Malice]

Was there not a bit of confusion also caused by the use of the 'R' Suffix?

Almost certainly, I do agree that "R" for distant doesn't make much sense. (Though I suppose this is why they are now going for the "delta" symbol instead of a letter suffix)
Perhaps it shows that once "repeater" was a correct terminology at some level at some point, even though current signalling principles at least have moved away from it.

 

[matchmaker]

So what you have given is the common enthusiast definition for these things (and I think some drivers still think in these terms too).
But to modern signalling engineering standards there is no such thing as a "repeater" signal (except a "banner repeater", which is it's own quite separate thing), and "distant" as a term covers all signals which can't show red.

The difference you are trying to describe is in signalling engineering terms instead given by whether it is a "multiple aspect" or "semaphore" distant. Though, those words only refer to the operational meaning of the signal and not the technology of construction which are instead described by the terms "mechanical" and "colour light" in the signalling principles. I.E. you can have a "colour light semaphore distant" (what you call a distant) and a "multiple aspect colour light distant" (what you want to call a repeater) Both of these would have the triangle on their ID plate (known as a delta plate to those that invented the thing and called that by approximately nobody else) to show they can't show a red if they were designed to the most recent standards. Though to save confusion thankfully very few semaphore areas are likely to be resignalled to get such without being completely replaced.

A "colour light semaphore distant" is a contradiction. It's either semaphore or colour light.

 

[Tempest Malice]

A "colour light semaphore distant" is a contradiction. It's either semaphore or colour light.

I appreciate it isn't the common usage of the term among most, but "Semaphore" in signalling engineering terminology refers only to the one distant applying to all stop signals in the box operation, and not to whether the signal itself is mechanical or colour light. (I know that most (to be fair a majority of) people use semaphore as a synonym for mechanical signal, but within the engineering sphere this is not the case).

 

[MarkyT]

Almost certainly, I do agree that "R" for distant doesn't make much sense. (Though I suppose this is why they are now going for the "delta" symbol instead of a letter suffix)
Perhaps it shows that once "repeater" was a correct terminology at some level at some point, even though current signalling principles at least have moved away from it.

It kind of made sense in multiple aspect areas where there was no individual control nor often even an indication to the signaller of the distant signal, and it worked fully automatically according to the aspect sequence ahead. Principles also now require a manual control to be available to replace a distant even if it normally works automatically. Then it makes more sense to give it a separate ID number. The delta sign really just reminds crew that the signal cannot show a stop aspect, reinforcing locational awareness/route knowledge.

 

[Annetts key]

A distant signal is a signal that is provided so that a driver has enough warning about a stop signal ahead being at danger. That’s why the distance between the relevant distant signal and the signal at danger is spaced at a minimum of the service braking distance.

The above signals were in some areas known as colour light repeaters, often shortened to repeater. Because in track circuit block sections where two aspect colour light signals are used, normally all stop signals can only show a red or a green, hence the distant signal can only show a yellow or a green. Hence the distant signal “repeats” what the stop signal is doing.

It’s important to note that a distant signal forms part of the aspect sequence.

This is totally different to what a banner repeater signal does. A banner repeater signal is only provided if there is the possibility that the required sighting distance cannot be achieved for a signal (or there is an operational advantage for some other reason where there is an advantage in a driver being given an earlier indication).

A banner repeater signal does not form part of the aspect sequence. It only tells a driver if the signal it is repeating is showing danger or a proceed aspect. Although there is now a LED type that can also show green if the signal is also showing green. Banner signals are normally fairly close to the signal that they repeat, often less than 200 yards (183 metres) away.

In terms of the suffix used on signal name plates, this varied across different railways over time.

For Western, typically R was used for colour light distant / colour light repeater signals (mechanical signals normally did not have signal name plates originally).
Banner signals typically used P, some used R, and more recently they used BR.
On Western, most had the same prefix and number as the signal they are/were repeating. But this has changed under the more modern standards.

 

[Dougman]

Thanks all, very interesting.