Signalling at Dunkeld and Birnam.

[jadmor]

I have passed through Dunkeld and Birnam station on the Highland main line recently, and wanted to ask a couple of questions about the way this station is signalled.

there is a Home signal on the Up line (Southbound), but no subsidiary signal for the loop. i would assume this means that the loop is only used for down trains.

The up line approaching the station is protected by a Home signal with a subsidiary arm for the left-facing junction, and I believe that the right-hand line is bi-directional, with the loop only being used when trains need to,pass. However, there is only one Starter, DK20, positioned at the exit for the loop line. what aspect does this show when a train is leaving the station on the main line?

 

[MadMac]

Good article HERE on Dunkeld’s signalling.

...The box today controls a total of five semaphore arms, most notable of which is the tall up starting signal DK3 on a lattice post and close to the signal box. South of this is a bracket with junction arms DK21 for platform 2 (the loop) and DK22 for access to platform 1.

At the north end of the station, DK20 stands on a tall post and controls exit from the loop (platform 2), while at the north end of the loop stands up home signal DK2...

Part of this is a “hangover” from when Dunkeld could “switch out” e.g. on Sundays and all trains ran via the Up side.

 

[Gloster]

An article in the Winter 2025 edition of the journal of the Signalling Record Society provides a partial answer. At a number of passing loops in Scotland the Starting Signal on the Loop is Approach-Lit. If a train is going to approach it on the line to which it applies the signal illuminates and shows the appropriate aspect. At all other times it stays dark so as not to give a train on the other line a misleading aspect. I can’t find Dunkeld mentioned in the article, so I can’t say if that applies here.

When a train is passing on the Through Line the signal will be dark. I am not sure what the situation would be if one Down train passes another, if that is permitted.

 

[John Webb]

Have a look at this 1974 diagram for Dunkeld which, from your description, seems to be the same as at present.

Of note: Signal 22, the main signal allowing entry into the bi-directional platform line, is locked by the block - that is it can only be cleared to allow a train into the platform if the line beyond the platform is clear to Ballinluig, the next block post. So the driver knows they can proceed when station duties are completed.

(I'm uncertain if the line uses tokens of any form, physical or electronic. Possession of the correct token also reassures the driver they have permission to proceed.)

 

[MadMac]

An article in the Winter 2025 edition of the journal of the Signalling Record Society provides a partial answer. At a number of passing loops in Scotland the Starting Signal on the Loop is Approach-Lit. If a train is going to approach it on the line to which it applies the signal illuminates and shows the appropriate aspect. At all other times it stays dark so as not to give a train on the other line a misleading aspect. I can’t find Dunkeld mentioned in the article, so I can’t say if that applies here.

When a train is passing on the Through Line the signal will be dark. I am not sure what the situation would be if one Down train passes another, if that is permitted.

The loops in the 1979 Kingussie-Culloden Moor Resignalling, to give its official title, all work like that. Dunkeld is semaphore so that wouldn’t apply.

To answer your question re two down trains passing (presumably on one of the 1979 loops), perfectly possible. There was an instance in the early days where the Aviemore signalman ended up with one in a loop and one at each end: he did get out of the predicament with some unofficial talking past signals…..

== Doublepost prevention - post automatically merged: 17 Mar 2026 ==

Have a look at this 1974 diagram for Dunkeld which, from your description, seems to be the same as at present.
Of note:
Signal 22, the main signal allowing entry into the bi-directional platform line, is locked by the block - that is it can only be cleared to allow a train into the platform if the line beyond the platform is clear to Ballinluig, the next block post. So the driver knows they can proceed when station duties are completed.
(I'm uncertain if the line uses tokens of any form, physical or electronic. Possession of the correct token also reassures the driver they have permission to proceed.)

Ballinluig is long gone, it’s now Track Circuit Block to Pitlochry, which is controlled from a workstation in Stanley Junction. Dunkeld still works Tokenless Block to Stanley Junction.

 

[Gloster]

The loops in the 1979 Kingussie-Culloden Moor Resignalling, to give its official title, all work like that. Dunkeld is semaphore so that wouldn’t apply.

To answer your question re two down trains passing (presumably on one of the 1979 loops), perfectly possible. There was an instance in the early days where the Aviemore signalman ended up with one in a loop and one at each end: he did get out of the predicament with some unofficial talking past signals…..

Thanks. I interpreted the original question as saying that the Down Loop Starter (DK20) was a colour light. In that case it would be the driver’s route knowledge that would tell them to ignore 20 as it did not apply to their train and the Home had given authority to enter the section. (Unless, of course, 20 was showing clear, in which case there is definitely something wrong!)

 

[jadmor]

An article in the Winter 2025 edition of the journal of the Signalling Record Society provides a partial answer. At a number of passing loops in Scotland the Starting Signal on the Loop is Approach-Lit. If a train is going to approach it on the line to which it applies the signal illuminates and shows the appropriate aspect. At all other times it stays dark so as not to give a train on the other line a misleading aspect. I can’t find Dunkeld mentioned in the article, so I can’t say if that applies here.

When a train is passing on the Through Line the signal will be dark. I am not sure what the situation would be if one Down train passes another, if that is permitted.

Thanks for the response, although I don't think this would apply here as the home signals are still mechanical semaphores.

== Doublepost prevention - post automatically merged: 18 Mar 2026 ==

Thanks. I interpreted the original question as saying that the Down Loop Starter (DK20) was a colour light. In that case it would be the driver’s route knowledge that would tell them to ignore 20 as it did not apply to their train and the Home had given authority to enter the section. (Unless, of course, 20 was showing clear, in which case there is definitely something wrong!)

Sorry for not making that point more clearly. I hope to get down to Dunkeld one day and see what happens from the platform.

== Doublepost prevention - post automatically merged: 18 Mar 2026 ==

Have a look at this 1974 diagram for Dunkeld which, from your description, seems to be the same as at present.
Of note:
Signal 22, the main signal allowing entry into the bi-directional platform line, is locked by the block - that is it can only be cleared to allow a train into the platform if the line beyond the platform is clear to Ballinluig, the next block post. So the driver knows they can proceed when station duties are completed.
(I'm uncertain if the line uses tokens of any form, physical or electronic. Possession of the correct token also reassures the driver they have permission to proceed.)

Thanks for posting that. based on what I have seen from on board a passing train, that set up appears unchanged. I believe that the sidings will soon be replaced once work starts on the A9 upgrade, with new sidings being installed at Perth on the site of the "New Yard".

 

[Lucy1501]

IThe up line approaching the station is protected by a Home signal with a subsidiary arm for the left-facing junction

To be somewhat pedantic, that is a main signal not a subsidiary signal.

A subsidiary signal is a miniature arm underneath the main signal which is horizontally striped red-white-red. These act as calling-on, shunt ahead or warning signal, with a C, S, or W being shown behind the arm when cleared.

The equivalent in colour light terms is the subsidiary “cats eyes” position light found below a main signal used for shunting purposes and calling on. Warning signals in colour light terms are now replaced by delayed release from red for the most part.

 

[Altnashin]

With regards to signalling at Dunkeld, I have heard it discussed that it may be resignalled in the next few years, but there was also talk of it being tied in with the dualling of the A9.
Although as far as I am aware, there appear to be no firm plans as yet.

 

[matchmaker]

It's woth noting that the up starter (no. 3) still has its magnificent MacKenzie & Holland finial.