Signals

THE SIGNAL BOX


Railway signalling discussion

Signal Locking ?

British signalling of the past (UK, excepting Northern Ireland)

Signal Locking ?

Unread postby Paul_G » Tue Dec 6, 2016 10:43 am

Hi Folks

Could anyone confirm that if a distant signal is OFF it locks the Home(s) + Starter to OFF ? or can they be returned at any time ?
(mechanical semaphore practice)

The reason for my query is that in an emergency a signalman would have to return the distant before returning home or starter... so delaying an emergency stop

Come to think of it can any lever be put back in the frame at any time?

ie Does locking only ever keep levers in the frame ?

Regards

Paul G
Paul_G
Crossing box
Crossing box
 
Posts: 21
Joined: Tue Aug 23, 2016 12:57 am

Re: Signal Locking ?

Unread postby kbarber » Tue Dec 6, 2016 10:54 am

Paul_G wrote:Hi Folks

Could anyone confirm that if a distant signal is OFF it locks the Home(s) + Starter to OFF ? or can they be returned at any time ?
(mechanical semaphore practice)

The reason for my query is that in an emergency a signalman would have to return the distant before returning home or starter... so delaying an emergency stop

Come to think of it can any lever be put back in the frame at any time?

ie Does locking only ever keep levers in the frame ?

Regards

Paul G

In every case I can think of, distant off locks all related stop signals off. That is presumably the reason for the instruction that the distant should be put back 'as soon as the signalman is aware that the train has passed the signal' (please excuse any misquotation, I'm writing from memory).

There are innumerable cases where levers will be locked reverse. Clearing a signal through points reversed, for example. Likewise a FPL that stands 'normally out' will be locked reverse by signals cleared over the points, whichever way the points are set. Also where a closing lever is provided in a box on a single line, the distant levers themselves will be locked reverse by fully-reversing the closing lever.
User avatar
kbarber
Rest-day relief
Rest-day relief
 
Posts: 550
Joined: Tue Nov 13, 2007 7:12 pm
Location: London

Re: Signal Locking ?

Unread postby MRFS » Tue Dec 6, 2016 1:02 pm

kbarber wrote: Also where a closing lever is provided in a box on a single line, the distant levers themselves will be locked reverse by fully-reversing the closing lever.


Even when the switched out box became a gate box?
ND: Why is there a door handle on the inside of my airing cupboard?
MF: Because it's the fire exit from Narnia.

I like David Lynch films. I don't consider incomprehension to be a barrier to enjoyment.
User avatar
MRFS
Moderator
Moderator
 
Posts: 3566
Joined: Thu Nov 8, 2007 9:29 pm
Location: ex cathedra cantuar

Re: Signal Locking ?

Unread postby Paul_G » Tue Dec 6, 2016 4:14 pm

Many thanks guys, I am sure there is a "prototype for everything" ... the "general" arrangement was what I was after..

Now to make it all work :-0

Cheers

Paul G
Paul_G
Crossing box
Crossing box
 
Posts: 21
Joined: Tue Aug 23, 2016 12:57 am

Re: Signal Locking ?

Unread postby kbarber » Wed Dec 7, 2016 9:23 am

MRFS wrote:
kbarber wrote: Also where a closing lever is provided in a box on a single line, the distant levers themselves will be locked reverse by fully-reversing the closing lever.


Even when the switched out box became a gate box?

Now that adds a complication even my devious mind didn't come up with... Examples? Or are you hypothesising?
User avatar
kbarber
Rest-day relief
Rest-day relief
 
Posts: 550
Joined: Tue Nov 13, 2007 7:12 pm
Location: London

Re: Signal Locking ?

Unread postby Fast Line Floyd » Wed Dec 7, 2016 1:49 pm

Electrically locked frames such as the Westinghouse L and the Siemens equivalent would allow the stop signals to be replaced to danger which in turn would place the distant to caution automatically but the stop signal levers would be held in the 'B' lock position until the distant lever was normalised (and any approach locking had released).
Graham
User avatar
Fast Line Floyd
Main line box
Main line box
 
Posts: 1639
Joined: Tue May 26, 2009 11:42 am
Location: Raunds

Re: Signal Locking ?

Unread postby MRFS » Wed Dec 7, 2016 2:46 pm

kbarber wrote:
MRFS wrote:
kbarber wrote: Also where a closing lever is provided in a box on a single line, the distant levers themselves will be locked reverse by fully-reversing the closing lever.


Even when the switched out box became a gate box?

Now that adds a complication even my devious mind didn't come up with... Examples? Or are you hypothesising?


I'm pretty sure that I've come across it in a couple of places, but can't remember exactly when - my GSR GA is with Richard Huss (of this parish) and I'm pretty sure in the listing there were a couple of places that had long/short section switching and then became gate boxes at night. I may also be thinking of antipodean practice too.

All it would need would be a further conditional lock slotted in with the gate lever (or a supplementary 'gate lever' - in practice an Annetts Key locked lever that would be used only by the night gate person).
ND: Why is there a door handle on the inside of my airing cupboard?
MF: Because it's the fire exit from Narnia.

I like David Lynch films. I don't consider incomprehension to be a barrier to enjoyment.
User avatar
MRFS
Moderator
Moderator
 
Posts: 3566
Joined: Thu Nov 8, 2007 9:29 pm
Location: ex cathedra cantuar

Re: Signal Locking ?

Unread postby hussra » Wed Dec 7, 2016 4:53 pm

MRFS wrote:I'm pretty sure that I've come across it in a couple of places, but can't remember exactly when - my GSR GA is with Richard Huss (of this parish) and I'm pretty sure in the listing there were a couple of places that had long/short section switching and then became gate boxes at night. I may also be thinking of antipodean practice too.

All it would need would be a further conditional lock slotted in with the gate lever (or a supplementary 'gate lever' - in practice an Annetts Key locked lever that would be used only by the night gate person).

I do indeed have your GSR GA here on my desk, but a quick search has not turned up the relevant info.

The DI will be along shortly to tell us off for talking about Irish railways other than in the Overseas forum, but just briefly: on the BCDR, Ballygowan and Dundrum both had level crossings and in 1926 were equipped with Sykes Switch for switching out. A 3 lever ground frame controlled the level crossing, and slotted the relevant home/starting and distant signals; the distants were fixed at caution when the box was switched out.
hussra
Branch line box
Branch line box
 
Posts: 108
Joined: Wed Jun 18, 2008 6:22 pm


Return to Signalling - historical

Who is online

Users browsing this forum: Bing [Bot] and 5 guests