Signals at Holborn Viaduct help please.

[simon b]

Hi all, I've been playing about with a model of Holborn viaduct in the early 70's but I'm a little confused on how some of the platforms were signaled.

 

When  platforms 1,4 and 5 were extended for 8 car trains, a train in any one of these would block the exit from the shorter platforms 2 and 3. Now this meant that the shorter platforms were used for parcel traffic only. What I cant figure out is that there doesn't appear to be any signals on these short platforms in the pictures I've seen of them.

 

Were these perhaps just provided with a calling on signal to pull up to the starter at the end of the long platforms? Or were they operated with no signals at all? 

 

I don't think there would have been a full size platform starter for these short platforms, as in theory the train would have to pass the following signal at danger? 

 

Anybody able to shed some light as to how it was done?

[bécasse]

John Hinson's website includes the diagram for the 1920s (post-electrification) colour-light signalling although it doesn't show the two "parcels" platforms 2 and 3 shortened as it should. Platform 6 was also effectively short although a narrow (certainly sub-standard width) walkway was provided throughout an 8-car length.

 

There were 2-aspect (both running and subsidiary) R/G signals on each road that converged prior to fouling points, the running signals being unable to clear unless the running signal in advance was also clear. Quite an interesting bit of early colour light signalling in fact.

 

The signalling shown in John Hinson's diagram remained in use until at least the late-1950s.

[simon b]

11 hours ago, bécasse said:

John Hinson's website includes the diagram for the 1920s (post-electrification) colour-light signalling although it doesn't show the two "parcels" platforms 2 and 3 shortened as it should. Platform 6 was also effectively short although a narrow (certainly sub-standard width) walkway was provided throughout an 8-car length.

 

There were 2-aspect (both running and subsidiary) R/G signals on each road that converged prior to fouling points, the running signals being unable to clear unless the running signal in advance was also clear. Quite an interesting bit of early colour light signalling in fact.

 

The signalling shown in John Hinson's diagram remained in use until at least the late-1950s.

 

Many thanks for that link, there used to be a lot more there than I thought. 

 

I'm still a little confused by it though. If I understand correctly there was a 2 aspect red/green signal protecting the points where the platform lines converge, but what was the subsidiary signal for? Was it effectively a distant signal for the following running signal or am I misunderstanding the diagram?

 

I've found this later pic that appears to show a single aspect signal part way along platform 5.  

 

[simon b]

So looking at these mock up pics I would need 2 aspect signals on platforms 1-4 to protect the converging tracks, then 4 aspect signals at the ends of platforms 1, 4 and 5? What was platform 6 is just a short loco spur so not an issue, and the widened lines connection doesn't exist on this version.

 

[bécasse]

15 hours ago, simon b said:

 

 

 

I'm still a little confused by it though. If I understand correctly there was a 2 aspect red/green signal protecting the points where the platform lines converge, but what was the subsidiary signal for? Was it effectively a distant signal for the following running signal or am I misunderstanding the diagram?

 

I've found this later pic that appears to show a single aspect signal part way along platform 5.  

 

The subsidiary signal was just that, it allowed movements as far as authorised just as any shunt signal would. Without the locking diagram, I can't be sure whether it could be cleared without the subsidiary signal ahead also being cleared (exactly as the running signal would only clear when the running signal ahead was showing at least single yellow), if it could it was just to allow movements short of the fouling point and may well have required the station foreman to stand at the fouling point with a red flag/lamp to ensure that the movement stopped short; although it seems unlikely it is possible that such moves were allowed to better position a van in the train (the station was alive in the early hours of the morning with newspaper traffic).

The "single" aspect signal that you think you can see is in fact a 2-aspect (and hence 2-hood) signal in a 3-aspect head - the Southern Railway didn't use 2-aspect heads (except, possibly, as IBSs or distants within a semaphore signalled area).