Signals

THE SIGNAL BOX


Railway signalling discussion

Worcester Mechanical Boxes

Current and future British signalling (UK except Northern Ireland)

Re: Worcester Mechanical Boxes

Unread postby Tulyar15 » Wed Mar 16, 2016 4:15 pm

I'm planning to spend the early afternoon at Worcester Shrub Hill tomorrow as several freight trains are due. In addition, Adrian the Rock tells me:-

"Just in case any of you don't already know and are interested,
extra trains are running from Foregate St to Cheltenham and back
between from today until Friday for the Cheltenham Festival.

The times are:

WOF d 0951
CNM d 1852 (WOS d 1921)

calling at Shrub Hill and Ashchurch.

I was around at WOS today when the return working came in - a
2-car sprinter and a 3-car 158 coupled together, and pretty well
loaded. After running on to WOF, it then ran back ECS to CNM.
Because P2 is occupied with LM ECSs at this time, it was given a
clear run through P1 in the up direction - the first time I've ever
seen that done at WOS".
User avatar
Tulyar15
Rest-day relief
Rest-day relief
 
Posts: 662
Joined: Fri Nov 9, 2007 11:59 am

Re: Worcester Mechanical Boxes

Unread postby Bob Davies » Wed Feb 1, 2017 9:07 pm

I am resurrecting this thread because I have had reason to spend some considerable time on Worcester Shrub Hill Station of late and one aspect of the signalling arrangements there puzzles me.

The question can be easily put by reference to Adrian the Rock's excellent webpages at http://www.roscalen.com/signals/Worcester/ and particularly the numbered plan. My question is why has signal SH83 got a distant arm under it when signal SH82 does not?
Bob D
User avatar
Bob Davies
Branch line box
Branch line box
 
Posts: 330
Joined: Fri Nov 9, 2007 8:32 pm
Location: Kidderminster

Re: Worcester Mechanical Boxes

Unread postby Is Line Clear » Thu Feb 2, 2017 12:22 am

Have spent a few days at Kidderminster last month (I had an annual meeting of SI's from preserved railways). Owing to some traffic problems I spent longer than expected at Worcester Shrub Hill. Not a problem for me. A lot of recent S & T renewal work is apparent. New signal wires and pulleys on metal stumps, new channel rodding and auto lubricators on cranks. Took lots of photos, including that lovely little (now refurbished) yellow shunt reading into Platform 1a from middle road if off). Not that many of those about now. Also the bracket with shiny LQ arms including distants, the centre pivoted starter (P2, is it) and the celebrated discs under the canopy - one a full size and below it a smaller one with legend 'CO'

An oasis is all you can call the whole area. Very interesting work for Signalmen, I think. To the uninitiated on a busy day it must be hard to work out where a train will arrive from and which way it will depart. Same with Foregate Street. BRILLIANT.

p.s. Shame about the UPVC windows on the SB's, but at least the boxes are still there.
7-5-5
Is Line Clear
Branch line box
Branch line box
 
Posts: 209
Joined: Fri Nov 9, 2007 10:05 am
Location: West Sussex

Re: Worcester Mechanical Boxes

Unread postby Danny252 » Thu Feb 2, 2017 10:20 am

Bob Davies wrote:My question is why has signal SH83 got a distant arm under it when signal SH82 does not?


Might I suggest going back to Page 1 of this thread? I think the discussion about distants, SH83, and exemptions from rule 39a cover your question!

Edit: I in fact meant Page 1 of a different Worcester thread! viewtopic.php?f=5&t=372
Last edited by Danny252 on Thu Feb 2, 2017 5:35 pm, edited 1 time in total.
Danny252
Rest-day relief
Rest-day relief
 
Posts: 695
Joined: Thu Aug 26, 2010 4:39 pm
Location: As close to the levers as they'll let me be

Re: Worcester Mechanical Boxes

Unread postby Bob Davies » Thu Feb 2, 2017 10:37 am

Danny252 wrote:
Bob Davies wrote:My question is why has signal SH83 got a distant arm under it when signal SH82 does not?


Might I suggest going back to Page 1 of this thread? I think the discussion about distants, SH83, and exemptions from rule 39a cover your question!

Danny - I have been to Page 1 and I can't see anything about SH83. The discussion there was about Tunnel Junction which is at the other end of the layout, and I can't in any case see what the connection between Rule 39a and the provision/non-provision of a distant arm is.

Can you point me to the specific reference?
Bob D
User avatar
Bob Davies
Branch line box
Branch line box
 
Posts: 330
Joined: Fri Nov 9, 2007 8:32 pm
Location: Kidderminster

Re: Worcester Mechanical Boxes

Unread postby S&TEngineer » Thu Feb 2, 2017 11:15 am

Bob, I have checked the wiring and control tables and these show that SH83 can be cleared up to SH82 at danger (with locked overlap) without any approach release controls. The distant SH84 can show single yellow when ON or double yellow when SH83 is OFF. Distant SH84 cannot show a green aspect.

So in effect the distant arm under SH83 is acting as an INNER DISTANT for SH82.
Regards,
S&TEngineer
-----------------------------------------------------
Out of this nettle, Danger, we pluck this flower, Safety.
Henry IV, Part 1, Act 2, Scene 3
User avatar
S&TEngineer
Moderator
Moderator
 
Posts: 1605
Joined: Fri Nov 9, 2007 8:17 pm
Location: Somewhere in the far South West

Re: Worcester Mechanical Boxes

Unread postby Danny252 » Thu Feb 2, 2017 5:34 pm

Bob Davies wrote:Can you point me to the specific reference?


I must apologise - I had searched for references to the signal, come across a four-page thread on this forum, and assumed it was the same as this one. It appears it was not!

This is the thread I came across: viewtopic.php?f=5&t=372
Danny252
Rest-day relief
Rest-day relief
 
Posts: 695
Joined: Thu Aug 26, 2010 4:39 pm
Location: As close to the levers as they'll let me be

Re: Worcester Mechanical Boxes

Unread postby Bob Davies » Thu Feb 2, 2017 5:40 pm

S&TEngineer wrote:Bob, I have checked the wiring and control tables and these show that SH83 can be cleared up to SH82 at danger (with locked overlap) without any approach release controls. The distant SH84 can show single yellow when ON or double yellow when SH83 is OFF. Distant SH84 cannot show a green aspect.

So in effect the distant arm under SH83 is acting as an INNER DISTANT for SH82.

I understand what is being done, and I accept that layout changes and box abolitions at Worcester posed some challenges but isn't this mixing up mechanical and colour light practice? You wouldn't normally expect to find a distant for an inner home under the outer home, even if it was fixed and there surely cannot be braking distance between SH83 and SH82 even allowing for the PSR through Shrub Hill Station.

Still, that is what is there and has been there for a number of years so who am I to question it? Thanks for finding the details for me, Chris.
Bob D
User avatar
Bob Davies
Branch line box
Branch line box
 
Posts: 330
Joined: Fri Nov 9, 2007 8:32 pm
Location: Kidderminster

Re: Worcester Mechanical Boxes

Unread postby S&TEngineer » Thu Feb 2, 2017 5:53 pm

Bob Davies wrote: You wouldn't normally expect to find a distant for an inner home under the outer home, even if it was fixed and there surely cannot be braking distance between SH83 and SH82 even allowing for the PSR through Shrub Hill Station.

But the SH82 braking distance runs from the distant SH84 at double yellow to SH82 at danger, not just SH83 to SH82. I'm away from the drawings at the moment but I think its over one mile.

There were a lot of these WR rationalisation schemes in the late 1960s to mid 1970s and its probable they were working to very strict budgets and had to keep the schemes as simple as possible from a technical perspective. When Truro was rearranged in similar circumstances the outer home T2 was made a 3-aspect colourlight but it functioned exactly the same as SH83 but in that case was at braking distance from the inner (mechanical) home T3. In the case of Worcester its possible they didn't want to move SH83 out to braking distance from SH82 and have to make it a colourlight signal. Anyway, we have no way of really telling after nearly 45 years.

Out of interest there is a video on the 'Adrian the Rock' excellent website that shows the SH83 to SH82 move in operation: https://youtu.be/f1t-cSJNedw
Regards,
S&TEngineer
-----------------------------------------------------
Out of this nettle, Danger, we pluck this flower, Safety.
Henry IV, Part 1, Act 2, Scene 3
User avatar
S&TEngineer
Moderator
Moderator
 
Posts: 1605
Joined: Fri Nov 9, 2007 8:17 pm
Location: Somewhere in the far South West

Re: Worcester Mechanical Boxes

Unread postby Bob Davies » Thu Feb 2, 2017 6:33 pm

S&TEngineer wrote:But the SH82 braking distance runs from the distant SH84 at double yellow to SH82 at danger, not just SH83 to SH82. I'm away from the drawings at the moment but I think its over one mile.
Fair comment, but I still don't like the arrangement!!
Bob D
User avatar
Bob Davies
Branch line box
Branch line box
 
Posts: 330
Joined: Fri Nov 9, 2007 8:32 pm
Location: Kidderminster

Re: Worcester Mechanical Boxes

Unread postby John Hinson » Thu Feb 2, 2017 7:31 pm

S&TEngineer wrote:Bob, I have checked the wiring and control tables and these show that SH83 can be cleared up to SH82 at danger (with locked overlap) without any approach release controls.

What and where is the overlap? I see nothing wrong with the arrangement if the signal is being worked like an IB in rear but even allowing for the foreshortening in Adrian's video there doesn't seem to be adequate distance between the DMU and the HST that is waiting to depart in the other direction.

The most recent plan I have is 1974 but is shows the Down Inner Home as a mere 145 yards from the box and the Down Platform to Up Main Starter as 60 yards. That's 205 yards and certainly not enough under the regulations at that date to permit the move shown in the video unless special instructuions were in place.

So put the clock back to when Wylds Lane box was there. Unless local instructions said otherwise, Shrub Hill Station would not accept a train from Wylds Lane unless there was 440 yards beyond the (now Inner) Home signal. It is only 323 yards from the Home to the big disc signal(s) half way down the station.

So unless the current Regulations allow an overlap on a semaphore of less than 205 yards, my humble opinion is that the signalling is not being worked as intended. The lack of approach control on a mechanical signal does not necessarily make it exempt from the old Rule 39.
S&TEngineer wrote:But the SH82 braking distance runs from the distant SH84 at double yellow to SH82 at danger, not just SH83 to SH82. I'm away from the drawings at the moment but I think its over one mile.

There were a lot of these WR rationalisation schemes in the late 1960s to mid 1970s and its probable they were working to very strict budgets and had to keep the schemes as simple as possible from a technical perspective. When Truro was rearranged in similar circumstances the outer home T2 was made a 3-aspect colourlight but it functioned exactly the same as SH83 but in that case was at braking distance from the inner (mechanical) home T3. In the case of Worcester its possible they didn't want to move SH83 out to braking distance from SH82 and have to make it a colourlight signal. Anyway, we have no way of really telling after nearly 45 years.

The braking distance is of no consequence because there is enough distance to stop at the Outer Home anyway.

Are you sure 84 signal shows double yellow? It certainly didn't in 1974 - I have two plans showing it as a two-aspect distant (it was once Wylds Lane's distant). So when or why did it change?

John
Image
‹(•¿•)›
User avatar
John Hinson
Site Admin
Site Admin
 
Posts: 6859
Joined: Thu Nov 8, 2007 1:13 pm
Location: at my computer

Re: Worcester Mechanical Boxes

Unread postby S&TEngineer » Thu Feb 2, 2017 8:02 pm

I'm away from the drawings at the moment so will come back on the overlap issue (of course I only look at it from a technical perspective and leave the operations side to other more expert people). Was the HST actually standing in the platform when the DMU approached SH82 or did it arrive after the DMU came to a stand at SH82? The control tables will tell us more.

There is a photograph of SH84 signal (showing double yellow) on Adrians website down the page here: http://www.roscalen.com/signals/Worcester/ShrubHill.htm

I photographed inside Shrub Hill signalbox not long after the revised arrangements were commissioned in 1973/4. Need to dig them out.
Regards,
S&TEngineer
-----------------------------------------------------
Out of this nettle, Danger, we pluck this flower, Safety.
Henry IV, Part 1, Act 2, Scene 3
User avatar
S&TEngineer
Moderator
Moderator
 
Posts: 1605
Joined: Fri Nov 9, 2007 8:17 pm
Location: Somewhere in the far South West

Re: Worcester Mechanical Boxes

Unread postby DaveHarries » Fri Feb 3, 2017 12:55 am

Heads Up!!
For anyone wanting last photos, note that Saturday 4th February will be the last day of operation for Norton Junction's semaphores NJ9 & NJ10.

A poster seen on another signaling forum states that, effective 0900hrs on Sunday 05th February 2017 the following signalling alterations will come info force at Norton Junction:

- Distant signal NJ8 will be relocated 400m nearer to Worcester and converted to an LED signal capable of displaying a yellow or green aspect.

- Semaphore signals NJ9 & NJ10, along with the semaphore distant (BA7654R) will be recovered and replaced with a new three-aspect LED colour signal with a position 4 junction indicator. :(

- The new signal will be located 5m nearer to Worcester and its ID will be NJ9

- The signal will be capable of displaying a Red, Yellow or Green aspect.

- Junction Indicator Position 4 will apply to the route towards Abbotswood Junction.

It will be a pity to see it go. Glad I got some photos while I could as I am not sure if time will permit on Friday and I am elsewhere on Saturday.

HTH,
Dave
Last Photo'd: June 2015
Yorkshire (Batley, Cattal, Hammerton, Kirkham, Kiveton Pk, Knaresborough, Poppleton), Teeside (Billingham), Northumberland (Bardon, Haydon Bridge, Hexham, Prudhoe, Wylam) & Lincolnshire (Roxton Sidings)


Next trip: TBC
User avatar
DaveHarries
Branch line box
Branch line box
 
Posts: 363
Joined: Tue Apr 19, 2011 10:55 pm
Location: Bristol, England

Re: Worcester Mechanical Boxes

Unread postby Danny252 » Fri Feb 3, 2017 9:40 am

S&TEngineer wrote:Was the HST actually standing in the platform when the DMU approached SH82 or did it arrive after the DMU came to a stand at SH82?


The film is a single continuous shot, and heat haze from the HST's lead unit is visible from 1:00 onwards in the bottom right corner. Additionally, a comment left by Adrian on the video states "The HST was actually a service from Paddington that terminated at SH and went back".
Danny252
Rest-day relief
Rest-day relief
 
Posts: 695
Joined: Thu Aug 26, 2010 4:39 pm
Location: As close to the levers as they'll let me be

Re: Worcester Mechanical Boxes

Unread postby S&TEngineer » Sat Feb 11, 2017 6:44 pm

Now had a chance to look at the drawings (Health Warning: These are dated 2002):

Home No.83 can be cleared with all track circuits clear and all points normal up to the opposing (Platform) Starting No.10 with Inner Home No.82 ESL. The distance (in effect the overlap; yes I know its a mechanical interlocking) between Inner Home No.82 and (Platform) Starting No.10 is 205yds. The distance from Home No.83 to Inner Home No.82 is 440yds. The distance from Distant No.84 to Home No.83 is 1374yds and the distance from Distant No.84 to Inner Home No.82 is 1814yds.

The mechanical locking prevents movements being made up to (Platform) Starting No.10 (at which the HST is stood) at the same time as movements from Home No.83 to Inner Home No.82. However, there do not appear to be any electrical controls that prevent such movements so it would appear that correct operation relies solely on signaller observation of the rules (i.e. ensuring trains have been brought to a stand at the applicable signal before an opposing movement is made).
Regards,
S&TEngineer
-----------------------------------------------------
Out of this nettle, Danger, we pluck this flower, Safety.
Henry IV, Part 1, Act 2, Scene 3
User avatar
S&TEngineer
Moderator
Moderator
 
Posts: 1605
Joined: Fri Nov 9, 2007 8:17 pm
Location: Somewhere in the far South West

PreviousNext

Return to Signalling - current

Who is online

Users browsing this forum: Bing [Bot] and 2 guests