Signal Boxes - different regions / companies

[Phil25]

Hello! This is my first post, so I am unsure if I should post it here.

British Railways were divided into regions. In these regions there were various signal boxes built by different companies. Many of them were later still operated by BR. The problem is that many companies had their own block instruments and bell codes, even after the railways were nationalised some bell codes were unique to areas such as western region or southern region. Hence, I am curious: how did two adjacent boxes with different block instruments and bell codes communicate? Also could anyone please provide me with some examples?

 

[Gloster]

Simply put, whenever you had two boxes working with each other but under different companies, etc., it would be agreed between the two companies that the line between them would be worked under the regulations used by company A. The signalmen at the box owned by company B would have to learn both their own regulations, as with any other signalman working for that company, and also those applying to company A.

Similarly, it would be agreed that company A would install the equipment over the line: whether company A had to maintain it or some of B’s linesmen were additionally trained for a new type of equipment would depend on the relationship. The signalmen at one box might have to learn how to operate an unfamiliar type of instrument, but this is nothing out of the ordinary for a signalman.

 

[matchmaker]

It was not I think always the case that different types of block instruments could not communicate with each other. It would depend on the types of instrument, but I think for example a Tyers Type F could communicate with a BR modular block as the basic mechanism and wiring would be similar. Others more knowledgeable might know for certain!

A useful source of information is The Signal Box www.signalbox.org

 

[Phil25]

Gloster thank you for your reply, I thought of that but thank you that you've explained this to me and also matchmaker i'm pretty sure that you can not have two different block instruments in two signal boxes but when you have a certain type of block instrument in box A there must be also a corresponding BI in box B. So if I understand correctly I guess this means that that one box adjacent to a box operated by different company would use both it's own BI and the other company's BI.

 

[4069]

Any block instrument using ordinary three-position three-wire block can communicate with another instrument using the same system, regardless of who manufactured each instrument. So, for instance, a box with BR standard "plastic" blocks can work with a box using LNWR Fletcher's blocks, Midland rotary blocks can work with Tyer's black boxes, and GWR disc and 1947 pattern instruments will work with Tyer's F blocks.

However, Sykes Lock and Block is a system in its own right, and can't work with anything else, and two-position and one-wire blocks also need matching instruments. Fortunately there aren't any of those left on NR.

 

[ChiefPlanner]

I believe that the Southern Region added an extra 3 on the is line clear bell codes for electric services , hopefully preventing routing of electric services onto non DC lines , though one wonders where they had in mind - London Bridge perhaps for steam /later diesel services.

Routing codes very much an alternative subject , I recall getting flummoxed at Walnut Tree Junction (Taffs Well) , where we had freights belled on with coal trains from Radyr being described as with engine and brake assisted in rear , followed by routing codes for either the Taff Main line or the "Big Hill" to Rhymney or short thereof. It all fell into place with some patient tuition.

 

[Dr Hoo]

The seminal events for this subject were the triple tail-end collisions (i.e. involving four passenger trains) in Canonbury Tunnel on 10 December 1881. This involved a Great Northern signalman at Finsbury Park fringing with a North London Railway signalman at Canonbury. Although passenger trains were involved they were successively offered forward with 'be ready' codes and 'seven bell' signals from Canonbury were interpreted as 'permissive acceptance' for the successive trains despite the block indicator remaining at Train On Line. The Inspector noted that a six bell Obstruction Danger should have been used.

Bell codes were standardised across all railway companies within the following three years. (There were still extra 'local codes' where necessary as noted above.)

[I have tried to explain a very complex situation in simple terms but apologies if I have got anything wrong. I hope that Forum members can at least get the general gist.]

 

[Cheshire Scot]

I believe that the Southern Region added an extra 3 on the is line clear bell codes for electric services , hopefully preventing routing of electric services onto non DC lines , though one wonders where they had in mind - London Bridge perhaps for steam /later diesel services.

In Scottish Region electric services had a 2 suffix - 3 1 2 for stopping passenger, 4 2 for express, 2 2 1 2 for ecs.

 

[Ashley Hill]

A retired signalman friend used to say that Newton St Cyres had a Western block on the Cowley side and a Southern block at the Crediton end. I have never seen an internal shot to confirm this.

 

[Gloster]

A retired signalman friend used to say that Newton St Cyres had a Western block on the Cowley side and a Southern block at the Crediton end. I have never seen an internal shot to confirm this.

As Newton St Cyres had a switch and was mostly switched out, that would only work if the two instruments were effectively the same technically, only with different casings. Otherwise Crediton would have to have two sets of instruments towards Exeter. More logical would be to have to an SR instrument in Cowley Bridge Junction that could work to both, but I can see the GWR saying, “We were here first: do it our way”.

 

[Sir Felix Pole]

As Newton St Cyres had a switch and was mostly switched out, that would only work if the two instruments were effectively the same technically, only with different casings. Otherwise Crediton would have to have two sets of instruments towards Exeter. More logical would be to have to an SR instrument in Cowley Bridge Junction that could work to both, but I can see the GWR saying, “We were here first: do it our way”.

Also Exeter West (GW) had to interface with Exeter Central 'B' (SR) - a train couldn't start for Central from St David's until line clear received from 'A' and 'B' to avoid stalling on the bank - not sure what the arrangements were there?

 

[Ashley Hill]

My friend also worked Exeter Central A (I’ve never asked about B). I’ll ask him next time I see him. Or perhaps someone from Exeter West at Crewe may know.
Presumably when their LSWR box existed one of the boxes at Cowley must have had the enemies block installed as I cannot imagine a Preece and a Spagnoletti working together.
G Pryer’s diagram book may have the answers but surprisingly I don’t own a copy.

 

[Gloster]

Also Exeter West (GW) had to interface with Exeter Central 'B' (SR) - a train couldn't start for Central from St David's until line clear received from 'A' and 'B' to avoid stalling on the bank - not sure what the arrangements were there?

I didn’t know Exeter Central A until long after B had gone, but I suspect it would be normal double-block working. West asks line clear from Central B, but the signalman at B doesn’t reply and put the block up to Line Clear until he has asked on to A and been given a Line Clear by the signalman there. You now have Line Clear on both Up Line instruments at B until West gives Train Entering Section. Once B had gone you had the whole length of the station platform for the train to run into once it has got over the top.

 

[Sir Felix Pole]

I didn’t know Exeter Central A until long after B had gone, but I suspect it would be normal double-block working. West asks line clear from Central B, but the signalman at B doesn’t reply and put the block up to Line Clear until he has asked on to A and been given a Line Clear by the signalman there. You now have Line Clear on both Up Line instruments at B until West gives Train Entering Section. Once B had gone you had the whole length of the station platform for the train to run into once it has got over the top.

Interesting, thanks. What instruments did 'A' and West have - I see that West's lever frame was renewed and expanded as late as 1959?

 

[Ashley Hill]

There’s an interior shot of Exeter Central A at the bottom of this link on Trainweb.

Salisbury to Exeter Signal Boxes (Page 2)

It shows a standard SR block at the Exeter West end. Pictures of Exeter West show all GW 47 blocks. Therefore SR and 47s must interface with each other.

 

[Gloster]

Interesting, thanks. What instruments did 'A' and West have - I see that West's lever frame was renewed and expanded as late as 1959?

Looking at the Signalling Record Society’s Signal Box Register: Volume 4, which I should have done earlier, it says that SR 3-position block was installed between Salisbury West and Exeter West 1957-1962 and seemingly retained after the regional change on the double-track until c.1985. It also says that TCB was in use Exmouth Junction-Exeter West in 1970, but that definitely does not fit my recollection and I reckon the date should be 1985.

A retired signalman friend used to say that Newton St Cyres had a Western block on the Cowley side and a Southern block at the Crediton end. I have never seen an internal shot to confirm this.

The Register says the Cowley Bridge-Crediton was Spagnoletti 1913-ca. 1960 and SR 3-position from then until 1985.

There’s an interior shot of Exeter Central A at the bottom of this link on Trainweb.

Salisbury to Exeter Signal Boxes (Page 2)

It shows a standard SR block at the Exeter West end. Pictures of Exeter West show all GW 47 blocks. Therefore SR and 47s must interface with each other.

I suspect that gradually during the grouping years common sense and pressure from the Inspecting Officers meant that the basic mechanics of the instruments had increasingly few differences between companies. However, each company would have its own style so that, although instruments could work with each other, you often couldn’t take a bit of an SR instrument and use it in a WR one as it just wouldn’t fit.

 

[Rescars]

However, Sykes Lock and Block is a system in its own right, and can't work with anything else, and two-position and one-wire blocks also need matching instruments. Fortunately there aren't any of those left on NR

Strying slightly from the OP, there were special arrangements at South Croydon, Purley and Maidstone East to enable Sykes Lock and Block working with adjacent mechanical signal boxes. These three boxes were equipped with special versions of the instruments incorporated into their miniature lever frames console. The tablets and treadles of these instruments did not drop with the 'thud' made by regular equipment, so were known as 'Silent Sykes' instruments.

 

[norbitonflyer]

I believe that the Southern Region added an extra 3 on the is line clear bell codes for electric services , hopefully preventing routing of electric services onto non DC lines , though one wonders where they had in mind - London Bridge perhaps for steam /later diesel services.

The different codes for electric and steam services was a factor in the Lewisham disaster in December 1957. Although all lines in the area were electrified, different codes were used - presumably so the type of train would be passed on, eventually to Sevenoaks which was then the limit of electrification, although it also indicated the kind of performance you might expect - electric trains have better acceleration and are therefore more able to recover from signal checks. Individual routes were not aprt of the bell codes - signalmen relied on the headcode on the front of the train for that, but the evening was foggy and so they were difficult to see.

The chain of events started when a Hastings train was offered forward to Parks Bridge Junction. It was one of the new diesel units, and there was at the time no consistency as to how to code them, being neither fish nor fowl - they behaved like electric trains but were not limited to electric tracks. The offering signalman coded it as electric, but as trains were running out of sequence the accepting signlman took the code to mean it was the electric unit he was expecting to send down the Hayes branch, and brought it to a stand awaiting an opportunity to route it across the flat junction onto the branch.

Whenn the route was eventually set up, the driver of the Hastings train spotted the wrong signal and didn't accept the route and so the signalling had to be timed out and a new route set up and accepted.

While this was going on, the next train (the real Hayes train) was brought to a stand at the previous signal, under the Lewisham flyover. Where it was hit in the rear by a steam train headed for the Thanet coast. The driver had missed the signals protecting the Hayes train because of fog and the tendency of smoke and steam to cling to the sides of the Bulleid Pacifics' air-smooted casings. The derailed vehicles also caused the flyover to collapse onto them, and a third train about to cross the flyover was only just stopped in time.

Had the signalman at Parks Bridge not misinterpreted the bell codes, it is probable that the collision would not have happened as the Hayes train would have been well down the branch before the Ramsgate train was anywhere near the area.

EDIT - I am reminded they were not actual bell codes but a telegraphic rotary train describer. The confusion was nevertheless caused by a limited number if pissible descriptions

 

[Gloster]

The different codes for electric and steam services was a factor in the Lewisham disaster in December 1957. Although all lines in the area were electrified, different codes were used - presumably so the type of train would be passed on, eventually to Sevenoaks which was then the limit of electrification, although it also indicated the kind of performance you might expect - electric trains have better acceleration and are therefore more able to recover from signal checks. Individual routes were not aprt of the bell codes - signalmen relied on the headcode on the front of the train for that, but the evening was foggy and so they were difficult to see.

The chain of events started when a Hastings train was offered forward to Parks Bridge Junction. It was one of the new diesel units, and there was at the time no consistency as to how to code them, being neither fish nor fowl - they behaved like electric trains but were not limited to electric tracks. The offering signalman coded it as electric, but as trains were running out of sequence the accepting signlman took the code to mean it was the electric unit he was expecting to send down the Hayes branch, and brought it to a stand awaiting an opportunity to route it across the flat junction onto the branch.

Whenn the route was eventually set up, the driver of the Hastings train spotted the wrong signal and didn't accept the route and so the signalling had to be timed out and a new route set up and accepted.

While this was going on, the next train (the real Hayes train) was brought to a stand at the previous signal, under the Lewisham flyover. Where it was hit in the rear by a steam train headed for the Thanet coast. The driver had missed the signals protecting the Hayes train because of fog and the tendency of smoke and steam to cling to the sides of the Bulleid Pacifics' air-smooted casings. The derailed vehicles also caused the flyover to collapse onto them, and a third train about to cross the flyover was only just stopped in time.

Had the signalman at Parks Bridge not misinterpreted the bell codes, it is probable that the collision would not have happened as the Hayes train would have been well down the branch before the Ramsgate train was anywhere near the area.

I can’t find the accident report as Railway Archives doesn’t seem to be working at the moment, but according to Tatlow’s book St John’s Lewisham (Oakwood, 2007) description was not by bell codes but by early train describers. These were clock like apparatuses that displayed the destination by an arrow pointing to it on one instrument and a second similar instrument that displayed the type of train. One problem was that it could only display one destination and type at a time and the signalman had to remember this at all times, including in the conditions and disorganisation that day. A second problem was that the number of types of train had increased beyond what there was space for and some had to be combined: the new Hastings diesels were shown as ’Main electric’.

 

[midland1]

Just had a quick look at Railways Archive and I got the report up no problem.

 

[matchmaker]

In Scottish Region electric services had a 2 suffix - 3 1 2 for stopping passenger, 4 2 for express, 2 2 1 2 for ecs.

I think that was not just Scottish Region - it was in the signalling regulations. In practice, at least on the North Clyde lines, the bell signals were sent so rapidly that every train was an "Obstruction danger"!

 

[Gloster]

I think that was not just Scottish Region - it was in the signalling regulations. In practice, at least on the North Clyde lines, the bell signals were sent so rapidly that every train was an "Obstruction danger"!

Not to a signalman: we could hear those infinitesimally short pauses…or maybe we just felt them.

 

[John Webb]

I think that was not just Scottish Region - it was in the signalling regulations. In practice, at least on the North Clyde lines, the bell signals were sent so rapidly that every train was an "Obstruction danger"!

My understanding is that 'Obstruction Danger' (OD) was to be preceded by a rapid series of rings as an urgent 'Call Attention' and then the 6 bells to be sent at a slowish rate to make clear it was OD. It's one bell code I don't think we've included in our simulator programming - perhaps I'll try it out the next time I'm at the box and see what our 'Raspberry PI' makes of it!

One Train Register Book page we like to exhibit at St Albans South, from April 1979, are the careful entries where the driver of a local down DMU has stopped at the Sandridge slow down line Home IBS signal to use the post telephone to report a passenger has pulled the communication cord, having apparently seen an obstruction on the fast lines. OD is sent, trains are stopped and cautioned and asked to proceed through the section to check the line and finally, nothing having been found 'Obstruction removed' (same as 'train out of Section' 2-1) is sent and recorded.

 

[Gloster]

My understanding is that 'Obstruction Danger' (OD) was to be preceded by a rapid series of rings as an urgent 'Call Attention' and then the 6 bells to be sent at a slowish rate to make clear it was OD. It's one bell code I don't think we've included in our simulator programming - perhaps I'll try it out the next time I'm at the box and see what our 'Raspberry PI' makes of it!

One Train Register Book page we like to exhibit at St Albans South, from April 1979, are the careful entries where the driver of a local down DMU has stopped at the Sandridge slow down line Home IBS signal to use the post telephone to report a passenger has pulled the communication cord, having apparently seen an obstruction on the fast lines. OD is sent, trains are stopped and cautioned and asked to proceed through the section to check the line and finally, nothing having been found 'Obstruction removed' (same as 'train out of Section' 2-1) is sent and recorded.

I was always taught, both on the Southern and Western Regions, to bang it straight out without a Call Attention; just send it as fast as you could without risking the relays holding up. However, looking in my old 1972 Regulations I see that at some point I have deleted the instruction at the beginning that says that Call Attention is not be used for Obstruction Danger. Well, old habits die hard.

 

[Phil25]

My understanding is that 'Obstruction Danger' (OD) was to be preceded by a rapid series of rings as an urgent 'Call Attention' and then the 6 bells to be sent at a slowish rate to make clear it was OD. It's one bell code I don't think we've included in our simulator programming - perhaps I'll try it out the next time I'm at the box and see what our 'Raspberry PI' makes of it!

One Train Register Book page we like to exhibit at St Albans South, from April 1979, are the careful entries where the driver of a local down DMU has stopped at the Sandridge slow down line Home IBS signal to use the post telephone to report a passenger has pulled the communication cord, having apparently seen an obstruction on the fast lines. OD is sent, trains are stopped and cautioned and asked to proceed through the section to check the line and finally, nothing having been found 'Obstruction removed' (same as 'train out of Section' 2-1) is sent and recorded.

Gloster is right, various sources that I remember having read mention that 6 is preceded without a call attention. However The Signal Box website mentions that a number of beats in rapid succession were used as emergency call attention in the Western Region (Bell signals in use in 1960). I haven't seen this in practice however, so I'm unsure when was that bell code used.

Also, do you guys happen to know if different token/staff instruments and instruments used in tokenless block could also interface with each other? Such a scenario would be very unlikely but just curious.

 

[Ashley Hill]

My understanding is that 'Obstruction Danger' (OD) was to be preceded by a rapid series of rings as an urgent 'Call Attention' and then the 6 bells to be sent at a slowish rate to make clear it was OD.

I have only ever sent 6 bells twice. The first time I sent the “emergency call attention “ as you described I received a querying phone call from the box ahead and questions from my inspector afterwards.

 

[Harpo]

One of the bigger signalbox differences still exists today in those with lever frames where the signaller faces the running lines and those where the signaller faces away.

Level crossings, token machines and the odd retro-fit mini panel are the only ‘sideways’ kit that comes to mind in mechanical boxes.

 

[Gloster]

One of the bigger signalbox differences still exists today in those with lever frames where the signaller faces the running lines and those where the signaller faces away.

Level crossings, token machines and the odd retro-fit mini panel are the only ‘sideways’ kit that comes to mind in mechanical boxes.

This was more of a difference due to when it was constructed. Early boxes were built so that the signalman could work the levers while looking out over the layout. Gradually more and more equipment was put on the block shelf and behind the frame: it seems that this lead to a decision to put the frame at the back so that the signalman could once more more get a clear view of the layout by turning his head. I believe that this was the reason for the change which started appearing around a hundred years ago.

Gloster is right, various sources that I remember having read mention that 6 is preceded without a call attention. However The Signal Box website mentions that a number of beats in rapid succession were used as emergency call attention in the Western Region (Bell signals in use in 1960). I haven't seen this in practice however, so I'm unsure when was that bell code used.

My guess is that the Emergency Call Attention was used for bell signals that were less urgent than Obstruction Danger, which is a ‘drop everything’ signal, but still urgent. I am thinking of Train Passed Without Taillamp to the box in advance or Stop and Examine if you want to catch the signalman before he pulls off his signals.

 

[Rescars]

Also, do you guys happen to know if different token/staff instruments and instruments used in tokenless block could also interface with each other? Such a scenario would be very unlikely but just curious.

Surely most sections would have had identical instruments at each end (otherwise the tablets/tokens/staffs wouldn't fit). [AMENDED] One variation would be the use of "no signalman" instruments which were operated by the guard or station staff. However adjacent sections might well have been equipped with different instruments. I am sure I have seen illustrations of boxes equipped with, for example, staffs for one section and tokens for the next. Tokenless block might have provided more opportunities for variations. Others will know much more.

 

[Gloster]

I went down into my garage to read the meters earlier and thought that at the same time I would collect my later (1981) signalling regulations loose-leaf file which was sitting on a shelf at the back. No, it wasn’t, and the chances of finding it in among the hundreds of books and magazines down there seemed dim, so I decided to make do with collecting a couple of maps. While doing that, what do I espy but the spine of a dark green loose-leaf file just poking out from under a box. Could it be..? It was.

It does say in Regulation 4.3 of the Signalmen’s General Instructions on a sheet reissued in October 1984 that Call Attention is not required for Obstruction Danger. I did think it a bit odd that this seemed to have disappeared (see #24) and, as said, I and everyone I worked with would just bang it out straightaway.