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Liskeard - closing switches

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

Liskeard - closing switches

Unread postby John Hinson » Tue Feb 14, 2017 8:08 am

A 1994 photograph - http://shop.studio433.co.uk/index.php?r ... t_id=11590 - reveals that Liskeard box had two block switches. Was this something to do with the Looe branch and if so, how did it work?

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Re: Liskeard - closing switches

Unread postby JRB » Tue Feb 14, 2017 9:04 am

It could just be a capacity problem, not enough contacts on the first switch and both worked together. Ideally they should be mechanically linked in such cases, but this was not always done.
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Re: Liskeard - closing switches

Unread postby John Hinson » Tue Feb 14, 2017 10:09 am

I have seen them linked with a bar. Surely it could cause serious irregularity potential by not linking them?

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Re: Liskeard - closing switches

Unread postby S&TEngineer » Tue Feb 14, 2017 11:20 am

I wonder if it was something to do with the fact that it was TCB with axle counters to Lostwithiel in the Down Direction but AB to St.Germans in the Up Direction? Regretably before my time in charge on that patch.
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Re: Liskeard - closing switches

Unread postby Mike Hodgson » Tue Feb 14, 2017 12:14 pm

Your photo seems to be at odds with Pryer's diagrams (vol 14)

These show in 1954 the line was worked by Spagnoletti block, and there was ONE closing switch, with siding working between branch and mainline stations.
In 1982 the line was worked by WR commutator block on main lines and the starters controlled by the block, with EKT on the branch between Coombe Jcn and the GF which had replaced ETS to the branch signalbox in 1964. Again ONE closing switch removed 27-04-98 when TCB introduced to Plymouth.
Perhaps it was stage works for the abolition of St Germans panel?

If the two were linked mechanically would the linkage necessarily be visible in photo? Would George Pryer have counted two linked switches as one ?

The branch seems to have had completely independent signalling system separated by sidings from the main line, so it ought not be relevant to the switch.
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Re: Liskeard - closing switches

Unread postby John Hinson » Tue Feb 14, 2017 12:46 pm

Well . . .

This picture shows a double-line block to St Germans and pictures of that "box" around the same time confirm a double-line block at that end:
http://shop.studio433.co.uk/index.php?r ... t_id=11589

This picture shows only a bell to Lostwithiel, although I canot be certain there isn't an instrument out of range of the picture:
http://shop.studio433.co.uk/index.php?r ... t_id=11591

So I don't think there was anything going on in preparation for the abolition of St Germans but the implication is that there is TCB in both directions to Lostwithiel, which presumably becomes AB if Liskeard closed?

That could account for the need of additional block switch contacts, but all that I have seen (including one I have in storage here) have a hefty bar connecting the handles. Even if this was fitted to the back (out of sight) there would surely be no need to provide two pins on chains (there is only one on mine, I'm almost sure). And, normally, they would be right next to each other. But if they are joined (or worked simultaneously) I guess they would count as one.

The only thing I can think would be needed on the branch would be releasing of signals for opposing directions.

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Re: Liskeard - closing switches

Unread postby Chris Osment » Tue Feb 14, 2017 1:41 pm

John Hinson wrote:The only thing I can think would be needed on the branch would be releasing of signals for opposing directions.


AFAIK once the separate branch box closed there were no signals on the branch at Liskeard (except perhaps a fixed Up Distant) anyway.
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Re: Liskeard - closing switches

Unread postby Mike Hodgson » Tue Feb 14, 2017 3:28 pm

Chris Osment wrote:AFAIK once the separate branch box closed there were no signals on the branch at Liskeard (except perhaps a fixed Up Distant) anyway.

That's exactly what Pryer shows as Liskeard's layout 15/6/81.
Stop boards in Down direction at the platform end and up direction at the GF
Crossover from branch to L&L Siding and its FPL worked by GF released by token.
Up main protected from L&L siding by a trap.
The separate branch box is shown as closing 15/3/64 replaced by GF, the branch run round loop points and signals being made spare a week earlier.
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Re: Liskeard - closing switches

Unread postby John Hinson » Tue Feb 14, 2017 5:21 pm

Thanks, Chris & Mike. Everything seems to point towards both switches applying to the main line, then - despite apparently not being linked.

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Re: Liskeard - closing switches

Unread postby GarthTilt » Tue Feb 14, 2017 6:24 pm

Regarding Mike's note that the Branch box closed on 15.3.64 it should read 8.3.64. 'Plymouth Engineering Notice No.153 dated 3rd March 1964 was an additional instruction to K2/10/64 and stated that all the work at Liskeard Branch, Coombe Junction and Looe will be carried out on Sunday 8th March. The first entry in the K2 was the following week in K2/11/64 (14-20 March 1964) as a 'new entry' stating that the work had already been carried out. So, George Pryer's, Tony Cooke's layout books and the SRS signal box register would appear to be in error. Amend your records accordingly!
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Re: Liskeard - closing switches

Unread postby Fast Line Floyd » Wed Feb 15, 2017 1:26 pm

One possibility not expressed here is that the second switch is a telecoms switch but the fact that it is not linked by a bar may well be that the people who installed it were either unaware of the linked switches or none were available at the time of installation.

My photo of the interior taken circa 1975 also shows only one switch.
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Re: Liskeard - closing switches

Unread postby Mike Hodgson » Wed Feb 15, 2017 2:17 pm

John Hinson wrote:Thanks, Chris & Mike. Everything seems to point towards both switches applying to the main line, then - despite apparently not being linked.

John


Yes indeed, but unfortunately we still haven't worked out why/when the extra contact(s) were needed.
Or whether George Pryer's "one closing switch" in 1982 was wrong, which seems less plausible than a week's discrepancy in the closing date of the other box. It seems more likely that some other change occurred between then and the closure of St Germans, necessitating another switch
Could it be something like monitoring of some AHB being moved to another box on closing?
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Re: Liskeard - closing switches

Unread postby John Hinson » Wed Feb 15, 2017 2:49 pm

Something clearly changed between 1975 and 1994, then, and I suspect the answer already lies here:

Mike Hodgson wrote:Yes indeed, but unfortunately we still haven't worked out why/when the extra contact(s) were needed.

Fast Line Floyd wrote:One possibility not expressed here is that the second switch is a telecoms switch but the fact that it is not linked by a bar may well be that the people who installed it were either unaware of the linked switches or none were available at the time of installation.

My photo of the interior taken circa 1975 also shows only one switch.

S&TEngineer wrote:I wonder if it was something to do with the fact that it was TCB with axle counters to Lostwithiel in the Down Direction but AB to St.Germans in the Up Direction? Regretably before my time in charge on that patch.

Switching though of SPTs from the TCB section could certainly be the reason, and would indeed be a non-critical occurrence if the switch wasn't turned. Intriguing though that neither switch is labelled.

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Re: Liskeard - closing switches

Unread postby JRB » Wed Feb 15, 2017 10:55 pm

I doubt that linked switches would have been available at that late date. No need for label when both should be operated together.
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Re: Liskeard - closing switches

Unread postby S&TEngineer » Thu Feb 16, 2017 11:15 am

......another spanner in the works. All the TCB section SPTs went to Lostwithiel box which controlled the Lostwithiel-Largin-Liskeard (exclusive) section. Only the Up Home at Liskeard had a telephone to Liskeard box.
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