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Swaynton Signal Box

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Re: Swaynton Signal Box

Unread postby davidwoodcock » Sun Aug 20, 2017 9:26 am

Chris Osment wrote:
davidwoodcock wrote:I think that Swaynton would still have had Preece's block instruments at the period of the model, a lot of ex-LSWR country main line did until more modern instruments were thrown up spare as a result of the introduction of c/l schemes for the two phases of Kent Coast electrification (1959/62).

I think that I am right in saying that Preece's instruments weren't (couldn't be?) interlocked with the signals, although a form of Sykes locking was used at certain locations which were considered high risk.


I not sure whether to agree or not...... For example, there was Preece 1-wire left between Poole B and Broadstone until about 1970, tho' perhaps by then it was so much of a backwater that no-one bothered to change it. On the other hand, I think that all the Preece had gone from the Salisbury - Exeter line by the mid-1960s.


Actually, I suspect that all the Preece instruments had gone from Salisbury-Exeter before the line was singled post the WR takeover. There was some mention of Preece's when I visited Andover Junction A in April 1963 - I hadn't knowingly heard of them before that - but I can't remember now whether that was because there was still at least one in the box (to Andover Town?) or because the bobby perhaps compared the "new" instruments with them. Certainly the men seemed to like Preece's which is perhaps why they lasted so long on main line duty. There were certainly some Preece's instruments in the elephant store at Wimbledon at that date, which strongly suggests that they were still in use somewhere on the Region - Wimbledon were great hoarders but the store wasn't a museum, everything held in it could be called upon to replace an in-use failed piece of equipment.
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Re: Swaynton Signal Box

Unread postby Brightspark » Sun Aug 20, 2017 4:19 pm

Chris Osment wrote:As mentioned elsewhere, given that 13PUSH is released by 7, and 15 locks 7, then there is no need for 15 to also lock 13PUSH. The other changes are for things which I thought might, or might not, have been done, so I'm relaxed about the changes :-)

My table was purely the Mechanical Locking. Earlier L&SWR diagrams had a separate Electrical Locking table added at the bottom in later years, while more modern SR versions had a ML table with the EL & Detection added to the right-hand side.


The Chiswick drawing has exactly that layout. I assume that the drawing I hold is showing the decommission of the box and the introduction of colour lights.
I have just sketched out the locking tray, based on the last table. Yes 15 doesn't need to lock 13Push for the reasons stated.

I'm still in two minds as to whether or not 14 should lock 9. After all, if you have 10 reverse and a train moving from the Up to the Down main and proceeding past 14, then in effect 9 becomes a facing point in rear of 14, so ought it not to be locked normal?


So far my locking tray has no conditional locking. Although I am puzzling how I could apply that should I need to.
I wonder if 9 is not locked because (a) it was too difficult to apply to a Stevens frame, (b) because it is expected that any movement would be a shunt move only within station limits in that direction and (c) to signal that move the bobby would have to be holding a flag and so couldn't pull the lever. Although the latter doesn't make sense for at Chiswick this move was signalled with a dolly.

Reading through the earlier posts I think that all is covered. 10 & 11 do eventually lock each other out by their relationship with other levers. 2 and 16 for instance.
3 & 14 when 10 reversed still do not lock each other out. But that has been covered, and I would need to add another trough.(notice the technical term added in there. That would be me studying the Binegar drawing)

As regards block locking of 3, 11 and 14. I can still squeeze this in, if I really want too. My thinking for keeping it is to stop the operators from driving trains up to the fiddle yard, or even into it when there is no road for it to go into. Especially as I am removing the Up Starter (currently situated beyond 11), not that stops anyone from stopping the train at the distant which they are often found doing. "Oh is that a distant, they all look the same to me." said an ex operator who is a fan of the line that has a Great Wait at Reading. Perhaps Western signals do all look alike?
For myself I would love to have some replica of Preece instruments. I think that it would add something especially if the centre operator was only signalling.

With that in mind, the locking tray remains as is with 9 troughs. I shall park the block locking for the moment as that used a trough to itself and I now need that for one of the longer links. I can retrofit this in should I need to at a later date.
So I shall continue to clean up the components for the tray and await any more comments regarding the locking. (and paint out the white lines on the levers)

Once again, thank all so much for your comments.

Andy

ps Swaynton will be at the Dorset Model Railway Exhibition in Wimbourne, 23rd to 24th Sept. Do say hello if you are there. Hopefully I should have some of this put together for viewing...unless someone spots something major.
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Re: Swaynton Signal Box

Unread postby Chris Osment » Sun Aug 20, 2017 5:40 pm

I've taken a look at the Chiswick drawing now - 'interesting' :-)

I was puzzled for a moment why you thought that the 'Line Clear' releases would require an additional locking trough, but I presume that you are referring to the model frame rather the prototype.

I have been to some of the Wimborne exhibitions in the past, but - on current plans - unlikely to be there this year. A shame, as otherwise I would have enjoyed watching the layout in operation. Mind you, I think anyone who can't tell a distant arm from a stop arm should be suspended from driving duties forthwith and sent for an eye test!
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Re: Swaynton Signal Box

Unread postby Brightspark » Sun Aug 20, 2017 9:19 pm

Yes, it was the Swaynton frame I was referring too.

It's trying to get decent operators who share our ambition. There is a shortage of them and many don't come up to scratch. Hopefully the new lever frame will sharpen the game. But I still expect the push/pull lever to be the source of much amusement. I can hear it now "it was really stiff to move and then it went loose. Do you need this bit?"

The Chiswick drawing I have is stamped 197247. The differences between it and Swaynton are the number of levers and the extra dollies. As well as the track detection.
The de-boarded posts look rather forlorn.
I spotted an error on the table, on 3, I think 17 should be 16.
I am also puzzled as to the release of 16. Does that mean that 16 works when 15 is either way? If so this is not reflected anywhere else in the table. Of course the information might be incomplete due to the drawing revision.

Right time to a neat drawing of the locking tray.

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Re: Swaynton Signal Box

Unread postby Chris Osment » Mon Aug 21, 2017 10:08 am

Brightspark wrote:I spotted an error on the table, on 3, I think 17 should be 16.


I suspect that it is simply a stray mark that got on the drawing and that 17 really is just 7.

Brightspark wrote:I am also puzzled as to the release of 16. Does that mean that 16 works when 15 is either way? If so this is not reflected anywhere else in the table. Of course the information might be incomplete due to the drawing revision.


Errr...yes and no :-) 16 is released by either 15 reverse or 12. If the latter, then of course 15 will be normal. Reference to the 'detection' section will show that 15 is indeed detected both ways.

What is more interesting IMHO is that 12 does not require 10 reverse, but in fact can be used to run wrong-road back through past the Up platform as far as disc 7. As a result you get quite a bit of complex conditional locking between the shunts at each end of the station, which luckily you avoid with Swaynton!
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Re: Swaynton Signal Box

Unread postby davidwoodcock » Mon Aug 21, 2017 11:35 am

Chris Osment wrote:
What is more interesting IMHO is that 12 does not require 10 reverse, but in fact can be used to run wrong-road back through past the Up platform as far as disc 7. As a result you get quite a bit of complex conditional locking between the shunts at each end of the station, which luckily you avoid with Swaynton!



I suspect that this reflects the fact that Chiswick was on a busy electrified route (and had been since 1915) where shunting moves had to be carried out expeditiously and so a (shunt) signal was provided to cover a potential move that would have been hand-signalled elsewhere even though the majority of shunt moves would have been at night (which in itself might have favoured the provision of a fixed signal rather than relying on a lamp).
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Re: Swaynton Signal Box

Unread postby Brightspark » Tue Aug 22, 2017 9:04 pm

Yes interesting indeed as my first question at the start of this topic was for such a move.
As you say fortunately Swaynton is a little simpler although Doug had planed for all those discs and the up advanced starter. But he was struggling to get that onto 17 levers.

Andy
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Re: Swaynton Signal Box

Unread postby Fast Line Floyd » Wed Aug 23, 2017 10:12 am

davidwoodcock wrote:
Chris Osment wrote:
What is more interesting IMHO is that 12 does not require 10 reverse, but in fact can be used to run wrong-road back through past the Up platform as far as disc 7. As a result you get quite a bit of complex conditional locking between the shunts at each end of the station, which luckily you avoid with Swaynton!



I suspect that this reflects the fact that Chiswick was on a busy electrified route (and had been since 1915) where shunting moves had to be carried out expeditiously and so a (shunt) signal was provided to cover a potential move that would have been hand-signalled elsewhere even though the majority of shunt moves would have been at night (which in itself might have favoured the provision of a fixed signal rather than relying on a lamp).

Chiswick outside the peak had two passenger trains per hour each way so shunting between them in daylight was very likely.
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Re: Swaynton Signal Box

Unread postby Brightspark » Thu Aug 31, 2017 10:04 pm

On the RMweb page I have posted an interesting pair of drawings that may have surfaced at Waterloo.
http://www.rmweb.co.uk/community/index.php?/topic/116799-swaynton-for-millcliffe-on-sea/

I am only trying to trump Chris's effort of course. :lol:
I have left the block locking on the table so I can work out where it would go should it be needed. Its a shame the Up block will have to action from either side.
If you would be so kind as to study my effort and check for errors please.

Thanks muchly

Andy
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