Holloway signalling query?

[Mickey]

A question regarding the individual Holloway North Up distant signals on the Up fast and Up slow lines?.

The Holloway North Up UP fast line and Up slow line individual semaphore distant signals that were carried underneath the Finsbury Park no.4 Up fast line and Up slow line semaphore starting signals (opposite East Goods) with the question being were these two individual distant signals that were worked by Holloway North Up somehow 'slotted' and could only have been pulled off to the clear position if and when Holloway South Up had also pulled off his Up fast line & Up slow line distant signals that were carried on a x4 doll wooden T-brack signal post that stood in between the Up fast & Up slow lines near to the top of the Holloway bank and not to far away from Holloway North Up box and was diagonally opposite to Holloway North Down. The reason for the question is the braking distance between the individual Holloway North Up home signals on the Up fast line and Up slow line wasn't to far away distance wise before reaching the Holloway South Up individual home signals on the Up fast line and Up slow line lower down the Holloway bank at Holloway South Up box.

[Mickey]

I don't know what the 'line speed' was down the Holloway bank when travelling along the Up fast line in the 1950s & 1960s from the top of the 'Holloway bank' down towards Belle Isle but maybe the line speed 'dropped down' from maybe 60 mph through Finsbury Park down to about 50 or 40 mph at Holloway North Up box situated at the top of the Holloway bank and then running onto a 'falling gradient' down the Holloway bank passed Holloway South Up box and on into Copenhagen tunnel and so possibly the signalling department back in the day thought it was adequate (or maybe it wasn't even thought of at all?) to just provide Holloway South Up box with a single semaphore distant signal for the Up fast line carried on a wooden T-bracket post with the arm for the Up fast line on the extreme right-hand side in amongst a group of x4 arms and situated at a rough guess about 350 yards from it's home signal further down the Holloway bank near to Holloway South Up box?.

Anyway considering the short distance involved on the Up fast line between the Holloway South Up Up fast line semaphore home signal carried amongst a group of x4 arms on the extreme right-hand side of a wooden T-bracket post and the Holloway North Up Up fast line semaphore home signal carried on a tall lattice T-brack post at the top of the Holloway bank possibly a 'outer semaphore distant signal' and carried beneath the Holloway North Up Up fast line semaphore home signal and worked by Holloway South Up box if provided may have been 'helpful to drivers' of trains travelling along the Up fast line between Finsbury Park no.4 and continuing along the Up fast line on a falling gradient passing Holloway South Up and onwards through Copenhagen tunnel to Belle Isle?.

[StevieG]

The situation on the Up, Mickey, with that relatively steep falling gradient after passing over Holloway Road, was obviously rather unlike that on the Down, where owing to the climb to the top of Holloway 'bank', the braking distance between North Down (ND) box's Distants (on South Down (SD) box's Homes), and ND's Homes (and, before that, between SD's semaphore Distants just at the exit from Copenhagen Tunnel, and SD's Homes), the braking distance was quite adequate.

So, on the Up I'm pretty sure that North Up (NU) box's Distants also had to act as distants for South Up (SU) box's stop signals, and to achieve that, such as definitely operated at Finsbury Park, Wood Green, New Barnet and Hatfield (and doubtless Hitchin), I think at Holloway what is often known as 'Indicator Working' was in play.
This was that, at the box in rear (would be North Up in your query Mickey), the Distant was not to be pulled until, in the rear box, a mechanical indicator behind the frame or electrical repeater on the block shelf, working from the wire or whatever, of the advance box (SU)'s Distant, had changed from 'ON' to 'OFF' (referred to by some as 'getting the slot').
In the particular case of SU's Up Distants being independent signals (i.e. not under NU's Homes), sited just beyond NU's complex pointwork, this meant that the six Distants were well sighted and easily applicable to approaching trains, no matter which line they were coming from at North Up : -
- (i.e. not only catering well for trains running Slow-->Fast, but moreso for those on the Up Goods, Coal, and Carriage ('Creep-up') Lines, remembering that North Up could turn trains on the Goods and Carriage to any of the four Up lines going forward; and those from the Up Coal could reach any Up road except the Up Fast).

Some railways used to enforce the correct (non-premature) operation of the rear box Distant by means of its lever being locked by a mechanical underbolt or an electric lock until the advance box had pulled his Distant 'Off', but AFAIK, in these GN boxes, correct working of these Distants relied only on the signalmen's adherence to the box instructions.

( There was one unusual exception at Hatfield No.2, where it was authorised that the Up Slow Distant there could be pulled without No.1 box's US Distant being 'Off' if the train was booked to call at Hatfield station.)

Of course, on other boxes or railways, another way of having a rear box distant apply to an advance box's stop signals, was to have it directly slotted by the advance box as well, so that both box's levers for the signal had to have been pulled for it to Clear.
But this often meant that the signal was quite a long way from the advance box, and therefore likely to be a really heavy pull. Presumably the GNR wanted to avoid that for some reason, adopting the 'Indicator Working' instead.

[Mickey]

Thanks Stevie an interesting post of yours. Yes I did wonder if it was the case between Holloway South Up and Holloway North Up that even though Holloway South Up had its own Up fast line semaphore distant signal situated near to the top of the Holloway bank and not far away from Holloway North Up box that the Holloway North Up signalman couldn't 'pull off' his own Up fast line semaphore distant signal (and the Up slow line distant signal as well) until the Holloway South Up signalman had also 'pulled off' along the Up fast line including 'his own' Up fast line distant signal so normally the Holloway North Up Up fast line distant signal would normally be either electrically or mechanically locked with the distant signal lever back in the frame but would become 'free' to be 'pulled off' once the Holloway South Up signalman had pulled off his Up fast line distant signal. Obviously when Holloway North Up was finally closed in 1970 and its Up fast line semaphore distant signal and Up slow line distant signal were both 'motorised' and was transferred and worked by Holloway South Up their wasn't an issue.

When I was a regular signalman at Junction Road Junction box between 1981-1985 on the Down T&H line coming from Gospel Oak and heading towards Upper Holloway the Junction Road Junction Down T&H line semaphore distant signal was mounted on a tall straight metal tubular post underneath the Gospel Oak Down T&H line starting signal and was located at Highgate Road on a curve at the top of a 'falling gradient' towards Junction Road box and this Junction Road Junction distant signal could only be 'pulled off' (along with the home and starter obviously being pulled off) when the old Upper Holloway box had 'pulled off' along the Down T&H line towards Harringay Park Junction box and when Upper Holloway had 'pulled off' along the Down T&H line a 'buzzer' would sound briefly inside Junction Road box and simultaneously release a 'electric lock' on the Down T&H line distant signal lever which by the way was worked via a signal wire from the box to the signal post.

[StevieG]

" .... so normally the Holloway North Up Up fast line distant signal would normally be either electrically or mechanically locked with the distant signal lever back in the frame but would become 'free' to be 'pulled off' once the Holloway South Up signalman had pulled off his Up fast line distant signal. .... "

Not really what I wrote Mickey. Please re-read this part of my post : -

" ..... Some railways used to enforce the correct (non-premature) operation of the rear box Distant by means of its lever being locked by a mechanical underbolt or an electric lock until the advance box had pulled his Distant 'Off', but AFAIK, in these GN boxes, correct working of these Distants relied only on the signalmen's adherence to the box instructions.

( There was one unusual exception at Hatfield No.2, where it was authorised that the Up Slow Distant there could be pulled without No.1 box's US Distant being 'Off' if the train was booked to call at Hatfield station.) .... "

[Mickey]

Yeah got it Stevie.

Interesting regarding Hatfield no.2 and the working of the Up slow line distant signal and that it could be 'pulled off' without Hatfield no.1 not having pulled off his Up slow line distant signal for trains running along the Up slow line towards Hatfield that were booked to stop at Hatfield.