Working a double track signal box

[Chris M]

I've read up about how signal boxes work and am interested in maybe trying to replicate just the  sounds of the bells you might hear if sitting on the platform on a summer's day near to a signal box with an open window. I just want to check that my understanding of how boxes were worked is somewhere near correct.

 

Assume that I am in box B controlling a section of double track main line. One side there is box A and in the other direction there is box C. There are no trains currently in my section so I am drinking my tea and having a read of the paper. I think the sequence of events is as follows:-

1. I get a single ding from box A to say "attention"

2. I reply with a single ding to say "I'm here and listening"

3. Assuming and express passenger is on the way I will then get 4 dings This is box A asking if I can accept  the train.

4. I reply with 4 dings to say yes I can accept it.

5. At this point the signalman in box A can set his starter signal to clear. Box B signals remain at stop.

6. I get 2 dings from box A to tell me the train has passed box A and is on its way to me.

7. Again I acknowledge with 2 dings back

7. Once the end of the train has passed Box A starter the signal is set to stop (or is danger a more correct term).

8. I then send the 1 ding for attention to box C and await 1 ding back.

9. I then send 4 dings and await 4 dings back.

10. Once I have the 4 dings response I can set my signals to clear.

11. The train passes so I send 2 dings to box C and reset my signals to stop (or danger) I get 2 dings back from box C.

 

For an "on platform" experience this would translate into a single ding from box A and quit soon after another 4 dings. After a while 2 dings from box A followed fairly soon but not straight away by 4 dings from box C. After the dings from box C the signals would move to clear.  After a few minutes (or less on my model) the train passes, the signals return to stop and maybe 2 dings are heard from box C or maybe these aren't heard due to the noise of the train. It would be very easy to replicate this with a some sets of bell codes on my smartphone and a sound pad app to select them in the correct sequence. I think it could make a train passing more of an event, I already have working signals which I use for every train that passes.

 

I hope the above sequence is somewhere near right but it would be good to hear from somebody who knows as I may well have misunderstood what I've been reading. I'm not worried about block instruments at this point as I am looking on this from the "on platform" experience rather than "in signalbox". When its very quiet on the SVR it is possible to hear the signalman sending messages but normally I just hear the messages received (the bells) rather than messages sent.

 

If there was also a train in the other direction would the dings from box C come through on the same bell equipment as dings from box A or would there be two different bells (maybe with different tones)? Clearly there would have to be a tool for sending messages to box A and a different one for messages to box C.

[Chris M]

I realise that any home signals can be set to clear before acceptance from box C; it is only the starter that must remain at danger until box C has accepted the train. Would it be normal for all the signals to be set to clear at the same time for a through train or was it common for the home signal to be set to clear when a train is accepted and then the starter left at stop until accepance form box C is received?

Edited May 4, 2021 by Chris M

[LMS2968]

Signalling isn't my strong point, but I have spent some time in boxes (usually drinking tea) waiting for a road for the train I was working. Generally, the single bell 'Call Attention' wasn't used unless Authority was in the area; and the bells for each direction would make a very different sound; a bell in one direction and a gong in the other, for example.

 

More knowledgeable people will be along soon, no doubt.

[beast66606]

12 I send 1 ding to box A who replies with 1 ding

13 I send 2 dings then 1 ding to box A (train out of section) who replies with 2 dings then 1 ding

 

 

Very simplistic but you are basically correct.

[beast66606]

13 minutes ago, Chris M said:

If there was also a train in the other direction would the dings from box C come through on the same bell equipment as dings from box A or would there be two different bells (maybe with different tones)? Clearly there would have to be a tool for sending messages to box A and a different one for messages to box C.

 

On a double track railway with normal absolute block there are 2 instruments, 1 to "talk" to A and 1 to "talk" to C - all communications (on the blocks) is done using these so when it's busy you have to keep your wits about you to make sure you understand what's being sent and received.

 

 

[LMS2968]

18 minutes ago, beast66606 said:

 

On a double track railway with normal absolute block there are 2 instruments, 1 to "talk" to A and 1 to "talk" to C - all communications (on the blocks) is done using these so when it's busy you have to keep your wits about you to make sure you understand what's being sent and received.

 

 

In theory, of course, you've written it all down in The Book (Train Register) as it happened. In practice, not always possible if things suddenly get hectic, which is when the memory cells get some exercise!

[meil]

48 minutes ago, Chris M said:

I've read up about how signal boxes work and am interested in maybe trying to replicate just the  sounds of the bells you might hear if sitting on the platform on a summer's day near to a signal box with an open window. I just want to check that my understanding of how boxes were worked is somewhere near correct.

 

Assume that I am in box B controlling a section of double track main line. One side there is box A and in the other direction there is box C. There are no trains currently in my section so I am drinking my tea and having a read of the paper. I think the sequence of events is as follows:-

1. I get a single ding from box A to say "attention"

2. I reply with a single ding to say "I'm here and listening"

3. Assuming and express passenger is on the way I will then get 4 dings This is box A asking if I can accept  the train.

4. I reply with 4 dings to say yes I can accept it.

5. At this point the signalman in box A can set his starter signal to clear. Box B signals remain at stop.

6. I get 2 dings from box A to tell me the train has passed box A and is on its way to me.

7. Again I acknowledge with 2 dings back

7. Once the end of the train has passed Box A starter the signal is set to stop (or is danger a more correct term).

8. I then send the 1 ding for attention to box C and await 1 ding back.

9. I then send 4 dings and await 4 dings back.

10. Once I have the 4 dings response I can set my signals to clear.

11. The train passes so I send 2 dings to box C and reset my signals to stop (or danger) I get 2 dings back from box C.

 

For an "on platform" experience this would translate into a single ding from box A and quit soon after another 4 dings. After a while 2 dings from box A followed fairly soon but not straight away by 4 dings from box C. After the dings from box C the signals would move to clear.  After a few minutes (or less on my model) the train passes, the signals return to stop and maybe 2 dings are heard from box C or maybe these aren't heard due to the noise of the train. It would be very easy to replicate this with a some sets of bell codes on my smartphone and a sound pad app to select them in the correct sequence. I think it could make a train passing more of an event, I already have working signals which I use for every train that passes.

 

I hope the above sequence is somewhere near right but it would be good to hear from somebody who knows as I may well have misunderstood what I've been reading. I'm not worried about block instruments at this point as I am looking on this from the "on platform" experience rather than "in signalbox". When its very quiet on the SVR it is possible to hear the signalman sending messages but normally I just hear the messages received (the bells) rather than messages sent.

 

If there was also a train in the other direction would the dings from box C come through on the same bell equipment as dings from box A or would there be two different bells (maybe with different tones)? Clearly there would have to be a tool for sending messages to box A and a different one for messages to box C.

4. set instrument to TRAIN ON LINE and then send 4

6. I get 2 dings from box A to tell me the train has passed box A and is on its way to me. Set instrument to TRAIN ON LINE

12 and 13 as in above post

[Gordon A]

I would have thought with an express passenger train not time tabled to stop in the area of Box B, that as soon as practical Box B has accepted the the express he would immediately bell Box C asking if he can accept the said passenger train.

That would give Box B time to come up with plan b if Box C cannot accept the express.

 

Gordon A

[meil]

1 minute ago, Gordon A said:

I would have thought with an express passenger train not time tabled to stop in the area of Box B, that as soon as practical Box B has accepted the the express he would immediately bell Box C asking if he can accept the said passenger train.

That would give Box B time to come up with plan b if Box C cannot accept the express.

 

Gordon A

That depends on the length of the Block Section.

[beast66606]

1 minute ago, Gordon A said:

I would have thought with an express passenger train not time tabled to stop in the area of Box B, that as soon as practical Box B has accepted the the express he would immediately bell Box C asking if he can accept the said passenger train.

That would give Box B time to come up with plan b if Box C cannot accept the express.

 

Gordon A

 

Not normally, only if train approach was authorised which is a special case, or in some odd cases where "offer on receipt" was authorised.

[Compound2632]

I had it described to me once, by someone who had started his career on the T side of S&T in the Thames Valley, how a train would be passed on to the box in advance from box to box, so that it was accepted beyond Oxford well before it had got to Didcot - presumably at an otherwise quiet time of day!

 

A rough calculation shows that this would likely have been early 60s.

Edited May 4, 2021 by Compound2632

[LNER4479]

8 minutes ago, beast66606 said:

 

Not normally, only if train approach was authorised which is a special case, or in some odd cases where "offer on receipt" was authorised.

Is this effectively the same thing as what I've heard referred to as 'double blocking' in reference to LNER running its high-speed, streamlined trains from 1935?

[Wheatley]

What Gordon said. In normal circumstances you would offer the train to C as soon as you had 'Train entering Section' from A. (i.e. unless the train was terminating at B or there was a reason why you couldn't, eg another train still in the section ahead or a local instruction).

 

You would also (normally) group bell signals if you could to avoid your mate next door having to get up too often. For example, if you were offered a train on the down at the same time as one was almost but not quite passing you on the up, you would normally send 'TES' for your up train back at the same time as accepting the down train. 

 

Less normal ut still widespread was the practice of giving 'One and unpeg' for 'Train out of Section', thus allowing your mate to merely look up from his Racing Post and make a mental note of the time instead of having to get up to answer the bell. If you got 1 back straight away then you sent the 2-1 as per the regs because that meant he had company and was standing by the bell for that reason. 

 

Bell signals from B might be audible on the platform as a 'thunk' depending on how hard the signalman at B was hitting the sender. There was a documentary on one of the TV channels some time ago about the boxes at Stockport which were, at the time, an Absolute Block oasis in a sea of TCB/MAS signalling - at one point the signalman being interviewed comments that his mate next door was obviously upset about something because he was getting 'sarcastic bell ringing', which completely stumped the interviewer but would have rung a bell (pun intended) with every signalman watching ! 

 

Then there was the "Barnsley Branch between 10 and 11 am on a weekday" soundtrack while six boxes were simultaneously working by omnibus telephone whilst listening to the 'Golden Hour':

 

"Be read on't up. 1977"

"Too early. On line."

"Must be after 1977, I'd left school when this came out. You can have 'Out' for than down man"

"Giz a slot Waddy"

"1978 ?"

"Sounds about right. Passing me on't up"

"WADD ! SLOT!!!"

"Got it. 'Be Ready' Don"

"Got him. You can have a 2-3 back when you're ready. Horse and cart for Leeds PCD"

"Shall I just come down there and get my own slot ?"

"When he retires I'm going to nail that ***** slot indicator to his mantlepiece as his leaving present..."

"Can't be 1978, she were still in that other group with him out of whatsname in 1978. 1980 ?"  

"At last, thank you"

"Sorry. What would I want with a slot on me mantlepiece ?"

"You can forget to tell your lass it needs dusting"

"Company..."

"Righto"

 

 

 

 

Edited May 4, 2021 by Wheatley

[beast66606]

1 hour ago, LNER4479 said:

Is this effectively the same thing as what I've heard referred to as 'double blocking' in reference to LNER running its high-speed, streamlined trains from 1935?

 

Train approach was used when a boxes distants were under the stop signals of the previous box, so in the case above Box A would offer to B who would offer to C, B would pull off and when B received train entering section from A would send "1-2-1" (Train approach) to Box C would would then offer to D and pull off, this was normally when there were a couple of boxes close together but generally the boxes on the line were far enough apart for normal block working to be used. eg Box A is point 0, Box B is 2 miles away but Box C is only 500yds from Box B. When boxes were close together the norm would be to offer on receipt and all would pull off as there wouldn't be time to give train approach between boxes before the train had passed the distant at caution.

 

Double blocking could either be

Using the idea of train approach to ensure the signals were clear in advance for the crack expresses

or

to provide extra protection for conflicts, lets say Box B is a junction and trains approaching from A would conflict with a branch train. A high speed train approaches Box A who offers it to Box B,  Box B ignores the code but offers the same train forward to Box C, if accepted by C, Box B then accepts the train from A (who clears his signals), and Box B can clear his signals also BUT if Box C cannot accept the train then Box B also refuses (ignores) the train, this provides double the protection for the junction as Box A cannot clear his signals so the train will be stopped there, if it overruns at A there is a lot more track for it to stop on before a collision could occur - useful with very high speed running when the brakes weren't as good as nowadays.

 

Nowadays this is (unofficially ?) known as a double red junction, even though the signal protecting the junction is safe as far as braking is concerned, the previous signal is also held at red to provide extra over run protection.

or

??? - maybe another alternative.

 

Without seeing the method of working I can't say for sure which is the case.

Edited May 4, 2021 by beast66606
added the bit about double red.

[The Stationmaster]

1 hour ago, LNER4479 said:

Is this effectively the same thing as what I've heard referred to as 'double blocking' in reference to LNER running its high-speed, streamlined trains from 1935?

LNER/ER/NERegion double blocking was normally to offer forward on receipt of the 'Is Line Clear?"  bell signal and not to acknowledge that signal until the train had been accepted by the 'box in advance.  The reason  for it was usually because of an increase in line speeds (or, more commonly, in train speeds) when distant signals had not been moved back to increase available braking distance.  It no doubt happened when the streamliners started running although the only instance I know of it (on the NE Region) was when the Deltics arrived.  Thus it wasn't applied for all classes of train but usually only for Class A/1 trains.

 

Therefore it is different from normal short section working where a 1-2-1 'Train Approaching' bell signal is used  although the 1-2-1 might still be used in connection with double block - it all depended on the siting of distant signals and the braking distance available as well as the length of the block section.  The 1-2-1 is used where there are relatively short sections as explained above - ECML double blocking didn't necessarily relate to the length of a block section but invariably related to inadequate braking distances.  

 

With ordinary 1-2-1 working there would always be a 'stop point' - i.e. the last box in the sequence of short sections would not offer the train forward on receipt of the 'Is Line Clear?' bell signal but would offer it on receiving the 1-2-1.

 

1 hour ago, Compound2632 said:

I had it described to me once, by someone who had started his career on the T side of S&T in the Thames Valley, how a train would be passed on to the box in advance from box to box, so that it was accepted beyond Oxford well before it had got to Didcot - presumably at an otherwise quiet time of day!

 

A rough calculation shows that this would likely have been early 60s.

I would be surprised that it went to that great an extent.  Appleford Crossing would have been the 'stop point'  for offering through on receipt of 'Is Line Clear?' for Didcot area 'boxes. and would only offer forward to Culham ('box closed in 1961) on receipt of the 1-2-1.  Culham might well have offered forward on receipt of the 'ILC?" while Nuneham 'box was still there but that was replaced by an Intermediate Block section in 1954 after which Culham definitely wouldn't have offered forward until he had 'Train On Line' from Appleford Crossing

 

It seems from what is known of the Signal Box Special Instructions that Radley offered forwards  on receipt of a 1-2-1 from Culham so Culham probably offered forwards some time after he received 'ToL' from Appleford otherwise the I.B section was serving no purpose at all.  Beyond Radley, after Sandford had opened during WWII, it was relatively short sections all the way to Oxford North Junction although Wolvercote Junction might have been the 'stop point' for offering forwards.  But it all depended on line speeds and train speeds and of course all passenger trains called at Oxford so it would be pointless to immediately offer those forwards before arrival.  It's very long time since i visited the station 'boxes at Oxford but that apart it was unusual to see signals cleared forthe majority of passenger trains to depart before it had arrived at the station.

 

When working out the use of the 'Train Approaching' and the associated pattern of offering trains through on receipt of the ''Is Line Clear?' several factors came into play.  The most important was ensuring that trains were not unnecessarily stopped but equally attention had to be given to the density of trafffic while bearing in mind any potential problems with sub-standard braking distances.  This made it quite a complicated job best worked out by making up a simple plan showing distances etc - a former colleague of mine had at one time been commended for producing a revised version of the Instructions for the signal boxes east of Cardiff General when he carried out a major review of how the 1-2-1 was used in that area.  the regulation itself was always the easy bit, working out how it should be applied - without tying up miles of railway was the bit which needed some specialist knowledge and skill.

[Compound2632]

1 minute ago, The Stationmaster said:

I would be surprised that it went to that great an extent.  

 

Well, one should make some allowance for the tale growing in the telling over a quarter-century. (The conversation I had with him was c. 1987. ) He also said how the telegraph wire fault-location test kit seemed like magic to the mechanically-minded signalmen. I assume it worked on reflection timing. It was another quarter-century before I was using the same test myself, on optical fibres.

[Mike_Walker]

2 hours ago, meil said:

4. set instrument to TRAIN ON LINE and then send 4

 

Should be LINE CLEAR not Train On Line.

[iands]

3 minutes ago, Compound2632 said:

 

Well, one should make some allowance for the tale growing in the telling over a quarter-century. (The conversation I had with him was c. 1987. ) He also said how the telegraph wire fault-location test kit seemed like magic to the mechanically-minded signalmen. I assume it worked on reflection timing. It was another quarter-century before I was using the same test myself, on optical fibres.

Ah, TDRs and OTDRs, clever pieces of kit, but that's going off topic so I'll stop.

[Grovenor]

3 hours ago, Chris M said:

I realise that any home signals can be set to clear before acceptance from box C; it is only the starter that must remain at danger until box C has accepted the train. Would it be normal for all the signals to be set to clear at the same time for a through train or was it common for the home signal to be set to clear when a train is accepted and then the starter left at stop until accepance form box C is received?

Not so, the home can only be cleared with the starter at danger when the approaching train is at or nearly at a stand and the driver is able to see the signal being pulled off and hence knows that the starter is at danger.

So norm is to clear in reverse order, starter, home, distant. If the train has not been accepted by C then all signals held at caution/danger until the train arrives at the home, then the home can be cleared to draw the train up into station limits.

Edited May 4, 2021 by Grovenor

[The Stationmaster]

12 minutes ago, Grovenor said:

Not so, the home can only be cleared with the starter at danger when the approaching train is at or nearly at a stand and the driver is able to see the signal being pulled off and hence knows that the starter is at danger.

So norm is to clear in reverse order, starter, home, distant. If the train has not been accepted by C then all signals held at caution/danger until the train arrives at the home, then the home can be cleared to draw the train up into station limits.

Agree that no signal can be cleared - Rule 39a as it once was.  

 

But clearing in reverse order was very much frowned upon on the Western (and of course sequential locking prevented it anyway where it was fitted) as it was regarded as a potentially unsafe way of working because it could encourage bad habits - such as a tendency to leave signals 'off or not apply the Regulations correctly at single line crossing stations.  Hence Signalmen were always taught to clear signals in the correct order (and, as I was taught, that they should be taken to task if they did otherwise; our Chief DI at Cardiff was very hot on it).

[Chris M]

Its very useful to know the correct (Western)  way of doing things. I shall set them to clear in that order. My distant signal is imaginary as I don’t have a quarter of a mile of line before my home signal.

 

Thanks for all the advice so far. I’ll build up some sound files and run a few trains based on this information. Now where can I get two different “dings”......

[Harlequin]

33 minutes ago, Chris M said:

Its very useful to know the correct (Western)  way of doing things.

 

Quote

I shall set them to clear in that order. My distant signal is imaginary as I don’t have a quarter of a mile of line before my home signal.

 

Thanks for all the advice so far. I’ll build up some sound files and run a few trains based on this information. Now where can I get two different “dings”......

Here's one source that I extracted some bell sounds from a while ago:

 

It's interesting that the people in the box seem to be griping about management and the world in general and when someone called "Mike" rings up the tone changes somewhat...

 

Edited May 4, 2021 by Harlequin

[The Stationmaster]

20 minutes ago, Harlequin said:

 

Here's one source that I extracted some bell sounds from a while ago:

 

It's interesting that the people in the box seem to be griping about management and the world in general and when someone called "Mike" rings up the tone changes somewhat...

 

Not me guv - although it was technically on my patch at one time but I was basically put in charge of the Western Valleys (or rather what was left of them).  i see the late turn Signalman was out not to make friends with various people - handling levers without a cloth was far from popular as it caused rust to develop on the lever handles and failing to observe the niceties of a certain Block Regulation (although commonplace) was a bit naughty while being filmed. 

[caradoc]

3 hours ago, Harlequin said:

It's interesting that the people in the box seem to be griping about management and the world in general and when someone called "Mike" rings up the tone changes somewhat...

 

 

Much more noteworthy would be railwaymen (anywhere) not griping about management !

 

[Michael Hodgson]

5 hours ago, The Stationmaster said:

Agree that no signal can be cleared - Rule 39a as it once was.  

 

But clearing in reverse order was very much frowned upon on the Western (and of course sequential locking prevented it anyway where it was fitted) as it was regarded as a potentially unsafe way of working because it could encourage bad habits - such as a tendency to leave signals 'off or not apply the Regulations correctly at single line crossing stations.  Hence Signalmen were always taught to clear signals in the correct order (and, as I was taught, that they should be taken to task if they did otherwise; our Chief DI at Cardiff was very hot on it).

 

The rule says "When a stop signal is at Danger the stop signal next in rear of it and worked from the same box must not be lowered for an approaching train until the train is close to such signal and has been brought quite or nearly to a stand"  This is a safety precaution against a driver missing the distant (easily done with drifting smoke) but carrying on at speed when he sees the Home SIgnal off only to find he doesn't have braking distance when he reaches the Starter at Danger.

It is perhaps worth pointing out that Rule 39a applies to semaphore signals, not to multiple aspect signals.  The reason why it doesn't apply to MAS is that such signals would show Yellow if the next signal were at Danger, so he will be see it at Caution unless the next signal has cleared in the meantime.

 

Clearing in Reverse order (ie pulling starter then home then distant) used to be the norm at wayside stations in the early days, at least on some lines, but as Stationmaster has said, this is now frowned upon to the extent that sequential locking was installed on busier lines to enforce current good practice.  

 

Offering on immediately is generally undesirable  as it reserves the route too far ahead - it can for example prematurely cause shunting to be stopped further along the line, or level crossings to be closed to road traffic too long before the train arrives.  Standard practice is to offer on to the next box when you receive train entering section, subject to local instructions (which will be displayed in the box) where it may be necessary to offer earlier or later, perhaps depending on the class of train.  

 

The OP said he can only hear the signals received, not sent on the SVR.  If you can stand right outside the box, you can often hear the tapper as signals are sent but the sound is naturally a lot quieter. 

 

LMS2968 said there was often a bell in one direction and a gong in the other, and the same applied to most boxes so that a signalman used to one box could learn another more easily.  This was true on quite a lot of lines, eg the GER.  The GWR tended to use bells with different tones, and had quite an impressive variety of different shapes making distinctive sounds.  The BR standard block instruments are available with several different size of bell to generate distinctive tones.

Failure to send Call Attention before offering a train is sometimes known as "sloppy working", frowned upon by many signalmen as well as by management.  Like most things in signalling there were  some exceptions.  For example a few very busy boxes were excused Call Attention, and on the MR which used the same bell for both Main and Goods roads, it was the rule that Call Attention was sent on the Main Line but omitted on the Goods Line (working by Telegraph Bells) - at least until that practice caused an accident.