Block Telegraph provided by GPO

[Nearholmer]

This may be really old news to signalling buffs, but I found this item displayed in our local museum, which has an incredibly good telegraphy and telephony gallery, full of stuff to play with, very interesting.

 

 

Which British lines availed themselves of this service?

 

Also, was ‘line closed’ a common term? I’m used to seeing ‘line blocked’.

[Boris]

21 minutes ago, Nearholmer said:

Which British lines availed themselves of this service?

 

Also, was ‘line closed’ a common term? I’m used to seeing ‘line blocked’.

Line closed was definitely used on some block instruments, I think some of the older AB machines on the Harrogate line have Line Closed as opposed to Line Blocked.  Our NER instruments at Weaverthorpe have Line Blocked.

 

Oddly enough the NYMR had an omnibus phone until recently between all of the offices at signal boxes south of Goathland that was run through the GPO and latterly BT, it was only removed because BT couldn't find the parts or knowledge to repair the line when it went wrong.  I suppose its a bit of a cheat but they also signal trains over the same sections using an internet connection in lieu of a block cable, so I suppose its kind of the same thing.

 

[micknich2003]

I will stand corrected, but I'm unaware of the GPO actually owning the instruments, though certainly in Ireland they maintained instruments etc.

 Conversely in England at least one railway conveyed public messages on behalf of the GPO.

 

[Tim V]

I think the West Somerset in the early days (1970s) used to run the token instruments via a GPO line, you had to bell slowly as the response times were long.

[Michael Hodgson]

I wasn't aware of mainland companies using the GPO to maintain block instruments, but it would certainly make sense for a smaller company to buy its instruments from the trade and contract the specialist maintenance out to the GPO telegraphs.  

 

The wording on that block seems to be the same house style (font/colour etc) as a standard LNWR Fletcher block, although it clearly isn't one as the pointers are different and the overall height is clearly also different.  The LNWR also used the term "Line Closed", that's quite a common wording.  So I am wondering whether that fascia is not original but a replacement in a routine overhaul some time after absorption of the company by the LNWR/LMSR. 

 

The NRM wording suggests they don't know which company it came from but suggest Ireland.  The LMS did have Irish operations of course.  Being sparsely populated Ireland did tend to have a greater proportion of single track lines so would have less need for double track blocks like this than mainland Britain.

 

[Nearholmer]

Interesting. And thanks for further education.

 

I must confess that when I saw it, my mind leapt to the idea that the GPO would "supply, deliver, install, set to work, and maintain", but now I see that it could be "maintain" only, and thinking further that could imply just the instruments (they'd have the skilled staff and workshop to look after them). The associated lines could have been GPO owned (routed off railway), GPO owned (routed on railway), railway owned (GPO maintained), or railway owned (railway maintained).

[ess1uk]

The token machines on the Heart of Wales line from Craven Arms to Pantyffynnon used to be carried on BT lines until a couple of years ago

[Michael Hodgson]

1 hour ago, ess1uk said:

The token machines on the Heart of Wales line from Craven Arms to Pantyffynnon used to be carried on BT lines until a couple of years ago

Well if you don't have a pole route, you've got to use somebody who has got one.

 

You can't just connect unmodified block instruments or token machines to a standard telephone line that is routed through the usual exchange switchboards etc - they need a continuous circuit, so special arrangements have to be made.

[ikcdab]

19 hours ago, Tim V said:

I think the West Somerset in the early days (1970s) used to run the token instruments via a GPO line, you had to bell slowly as the response times were long.

Yes, that's right, but from around late 1980s. The speed was dictated by a relay. The system had to have current for a second before the relay would pick up and send the bell signal forward. This was to weed out spikes on the BT line that might give a false "ding". So your bell plunges each had to be for at least a second. All very frustrating and later removed when the dedicated line was installed.

 

[ikcdab]

In the earliest days, the railway telegraph was also used to send public messages. This was before the GPO provided telephone services. So it is not a great leap of imagination for the GPO to take on maintenance of the instruments in later years.

Edited October 12, 2021 by ikcdab