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Distant signals in a very short section.


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10 hours ago, Michael Hodgson said:

Is there a "not" missing from the last sentence above?

 

 

My impression of the use of distant signals at stations big enough to have two (or more) boxes is that in practice distant off generally tells the driver of a train not booked to stop that he has a clear run right through the whole station, not just past the first box.  Other railways didn't use 2-2-2 but they often had other means (for example a mechanical or electrical indicator or slotting) of getting a box in rear to keep his distant on until they were ready for the train to proceed.

 

 

The GWR introduced the 2-2-2 acceptance to get round the problem of not having controls on the distant(s) of the box)es) in rear.  When the Regulation was amended at some date between 1924 and 1936 a new clause was added (Clause d in the 1936 and 1960 Regulation, Clause c in the 1965 amendment) saying that the 2-2-2 acceptance was not needed where distant signal controls were provided.  This of course was facilitated by the conversion of distant signal to electric operation although some companies used mechanical controls.    As Truro West's Up Distant was fixed at caution it could not have controlled Penwither's Jcn's Up MaIn distant because that would have meant that it too would have had to be fixed at caution.

 

As you'll be aware a big difference between the GWR (and WR in new work until well into the 1960s) was the impact of PROSs etc on whether or not a distant signal was worked or fixed at caution.  I think it is fair to say that there was a much greater preponderance of fixed distants on the GWR/WR than on any other company/BR Region.

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1 hour ago, The Stationmaster said:

As you'll be aware a big difference between the GWR (and WR in new work until well into the 1960s) was the impact of PROSs etc on whether or not a distant signal was worked or fixed at caution.  I think it is fair to say that there was a much greater preponderance of fixed distants on the GWR/WR than on any other company/BR Region.

I suspect that that is undoubtedly true of the pre-grouping era when many companies continued to use worked distants in situations where describing them as an over-provision would be putting it politely (the approach to most stations on a single line, whether passing loop or terminus, for example). 

 

However, the work of the various standardisation committees after the Great War, together with the urgent need to eliminate even minor unnecessary cost as the recession of the late 1920s began to bite, seems to have caused the other "big three" to adopt fixed distants in a big way. On the Southern not only were many previously worked distants fixed but in places where fixed signalling could be eliminated altogether (with the box retained as a GF to work the points) yellow marker lights replaced distant signals. (White marker lights were used to mark the approach to intermediate stopping places devoid of pointwork.)

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24 minutes ago, bécasse said:

On the Southern ....White marker lights were used to mark the approach to intermediate stopping places devoid of pointwork.

A distinction apparently not employed at Henstridge on the ex-S&DJR, where white marker lights appeared circa-1955 but the siding points remained in use until 1965 :-)

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16 hours ago, The Stationmaster said:

This might well come back to any modfied Clearing Points at Truro East and West and that PROSs through the station and when the two station 'boxes asked 'Is Line Clear?' forwards between each other' and the strong probability that 2-2-2 acceptances were also used

 

Let's assume for a moment that Truro West asked forwards on receiving the ILC? from Penwithers Jcn   If that was acknowledged and 'Line Clear' was pegged up by Truro East then West  could accept under full 'Line Clear' from Penwithers Jcn and the Penwithers Jcn Signalman could clear all his relevant Up direction signals including the distant.  If Truro East could not accept the train then West would implement Regulation 4A  (provided the line was clear to his Clearing Point) and the Penwithers Jcn Signalman would keep his Up Distant Signal at Caution  So there was clearly a situation in which Penwithers Jcn Signalman could clear his Up Main. Distant.

 

In the opposite direction things were different because Truro East had a full Clearing Point between his Down Main Home and his Inner  Home with the distant a very long way back from the Home.  So no restriction on acceptance from Probus (or Burngiullow when Probus was switched out or after it had been closed for good in 1965)  provided East's Clearing Point was not fouled.  But he could not clear all his Down Main stop signals and clear his Distant until the train had been accepted by Truro West under a full 'Line Clear.  So even if West accepted by 2-2-2 East could still accept under full Line Clear from Probus/Burngullow because his Distant had more than adequate braking distance to the Home Signal

 

In the Up direction if East accepted a train under Regulation 4A from West that still gives West a full Clearing Point so he could accept from Penwithers Jcn under a full 'Line Clear'.  It's interesting to note that according to George Pryer's diagram West did not have a two shot detonator placer on the Up Main Line but did have one on the Up Branch Line (the one between the two platforms which is nowadays the Up Main).  I suspect the reason for that was the very low PROS on the Up Main.

 

The big question which we don't know the answer to is what the Clearing Points were at both station 'boxes and if my assumption about possible Modified Clearing Points is correct or whether they had 4A acceptances between each other instead?  But even if West accepted 4A from East that would not affect East's acceptance from Probus and East would keep his Distant Signal at caution  As I said above an awful lot of this depends on what was in those Signal Box Instructions - West clearly had a potentially very short Clearing Point on the Down Main in any event.

 

Incidentally prior to the Knowle & Dorridge collision  (which involved the failure of a Signalman to properly apply Regulation 4A( application of the Regulation was effectively left entirely to the knowledge of the Signalman.  One of the consequnces of that collsion and the Inspecting Officer's Report was that its use was subsequently noted in the Signal Box Soecial Instructions at all places where it applied.  

 

Regulation 4A was amended in late 1965 and was removed completely from the Regulations booklet in the 1972 reissue.  However it did not disappear and was cinrinued in Signalbox Soecial Instrux ctions at those places were it still had any application.  This led to the strange situation of it no longer applying anywhere on the WR but still applying in at least one place which had been transferred frim the WR to the LMR.  Thus when i visited the 'boxes in the immediate Shrewsbury area c.30 years ago what had been GWR AB Regulation 4A was still in use and I even heard a 2-2-2 acceptance bell signal.  As little has changed at Shrewsbury since then it could wel be still in use there - 50 tears after it disappeared from the Absolute Block Regulations.

 

BTW. Oenwithers Jcn' Down was only 44o yds i. rear of the Home Signal so 4A presumably also applied there although the switchback gradient, albeit steep,. might have been considered to decide that it was not necessary.

Thanks for the explanation, I was a little uneasy about the fixed distant not always meaning to expect Truro West's  Up Home to always be at danger but driver knowledge must have covered that so if the driver saw Penwithers Junction Up Distant cleared then they would know they had the road into  the platform.

 

Regarding regulation 4A between the two  boxes,  the situation on  the down line is quite clear in the Truro East would have to maintain their distant at caution if West only accepted under 4A but what would regulation 4A achieve on the Up, considering that West's Distant was fixed at caution, it would stay that way even if East accepted under regulation  4.

 

Incidentally, after Probus closed  Grampound Road remained open through to 1972 (presumably just to break the very long section to Burngullow after all the sidings were taken out of use in the 1960s).

Edited by Zoe
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4 hours ago, Zoe said:

Regarding regulation 4A between the two  boxes,  the situation on  the down line is quite clear in the Truro East would have to maintain their distant at caution if West only accepted under 4A but what would regulation 4A achieve on the Up, considering that West's Distant was fixed at caution, it would stay that way even if East accepted under regulation  4.

From the Knowle and Dorridge accident report, a second requirement of Regulation 4A is that the signalman at the box in rear must keep all his signals at danger till the train is within his distant signal. At Truro West, this almost certainly means that the driver sees the home signal at danger before it is cleared, and it probably appears to the driver much like a Rule 39 (a) caution, even though it isn't.

 

I have become a lot more interested in what drivers were told about Regulation 4A, because it seems all very well signalmen having elaborate procedures to work, but they surely lose a lot of their effect if drivers don't know how to interpret the signals correctly.

 

An up train could approach Penwithers Junction, find the distant at caution because of Regulation 4A at Truro West, but find all the stop signals clear (because Regulation 4A appears not to require drivers to be cautioned, just that the stop signals mustn't be cleared until the approaching train has passed the distant - or, of course, Penwithers Junction could be switched out), then find Truro West up home at danger.

 

Rather more curiously, the driver of an up train could find all the signals, including the distant, off at Penwithers Junction (because Truro West accepted with a full Line Clear), yet still find Truro West home signal at danger because Truro East's acceptance was under Regulation 4A. I re-read the bit of the Knowle and Dorridge accident report, and it is clear that a Regulation 4A acceptance from the box in advance allows the signalman to give a full Line Clear acceptance to the box in rear:

Quote

This Regulation requires the signalman at Knowle and Dorridge to obtain "Line Clear", or "Line Clear to Clearing Point Only", from Lapworth hefore he gives full "Line Clear" to Bentley Heath Crossing for a train.

Admittedly, in this situation the line has to be clear to Truro East's clearing point, not merely clear to Truro West's clearing point, but it's still a stop signal at danger to the driver of the approaching train, and if the signalman happens to be engaged in other duties at the time, the signal might not be cleared before the train reaches it.

Edited by Jeremy Cumberland
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18 hours ago, Jeremy Cumberland said:

At Truro West, this almost certainly means that the driver sees the home signal at danger before it is cleared, and it probably appears to the driver much like a Rule 39 (a) caution, even though it isn't.

This doesn't seem ideal at all.  If after seeing Penwithers Junction Up Distant cleared, the driver assumes that they have the road into the platform at Truro then wouldn't the first  reaction after emerging from the tunnel be to slam on the emergency brake after seeing the Truro West Up Home at danger even if it does then get cleared?

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21 hours ago, Michael Hodgson said:

My impression of the use of distant signals at stations big enough to have two (or more) boxes is that in practice distant off generally tells the driver of a train not booked to stop that he has a clear run right through the whole station, not just past the first box.  Other railways didn't use 2-2-2 but they often had other means (for example a mechanical or electrical indicator or slotting) of getting a box in rear to keep his distant on until they were ready for the train to proceed.

From my LM colleagues (and on some SRS drawings I think) I have heard the term Underbolted.  Don’t know enough to know whether that was something like this or more akin to slotting, but clearly, the same concepts applied.

 

21 hours ago, The Stationmaster said:

Regulation 4A was amended in late 1965 and was removed completely from the Regulations booklet in the 1972 reissue.  However it did not disappear and was cinrinued in Signalbox Soecial Instrux ctions at those places were it still had any application.  This led to the strange situation of it no longer applying anywhere on the WR but still applying in at least one place which had been transferred frim the WR to the LMR.  Thus when i visited the 'boxes in the immediate Shrewsbury area c.30 years ago what had been GWR AB Regulation 4A was still in use and I even heard a 2-2-2 acceptance bell signal.  As little has changed at Shrewsbury since then it could wel be still in use there - 50 tears after it disappeared from the Absolute Block Regulations.

I heard 2-2-2 Acceptance used in Newbury West in Autumn ‘75.  Will have gone not long after with Berks & Hants resignalling.

 

Paul.

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21 hours ago, RailWest said:

A distinction apparently not employed at Henstridge on the ex-S&DJR, where white marker lights appeared circa-1955 but the siding points remained in use until 1965 :-)

Sorry, Chris, a senior moment! They were installed at the approach to some rural stopping places which were devoid of signals. I presume that the criterion for their installation was that there were no other distinctive markers  to aid drivers in determining their precise location. The yellow marker lights were always installed at the approach to termini without other signalling.

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1 hour ago, Mark Saunders said:

Bedlington South’s Down Section and Bedlington North’s Distant less than 300yardsto to the Home board!

 

Even shorter perhaps, circa-1900 the Up Distant for Highbridge 'A' box was underneath its own Up Home! Admittedly the latter was slotted as the Up Home for Highbridge 'A' and also  'B' had 'control' over 'A's Up Distant.

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22 hours ago, bécasse said:

I suspect that that is undoubtedly true of the pre-grouping era when many companies continued to use worked distants in situations where describing them as an over-provision would be putting it politely (the approach to most stations on a single line, whether passing loop or terminus, for example). 

 

However, the work of the various standardisation committees after the Great War, together with the urgent need to eliminate even minor unnecessary cost as the recession of the late 1920s began to bite, seems to have caused the other "big three" to adopt fixed distants in a big way. On the Southern not only were many previously worked distants fixed but in places where fixed signalling could be eliminated altogether (with the box retained as a GF to work the points) yellow marker lights replaced distant signals. (White marker lights were used to mark the approach to intermediate stopping places devoid of pointwork.)

Although most ex LSWR single lines in the West f England retained worked distants at crossing stations until the end whereas the GWR had done awauy with worked distants at crossing stations was back and su sequently only provided them where the provision of much higher turnout speeds allowed.   I think you'll find also that worked distants would have been used in equivalent places to the likes of Truro.

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The box instructions for Barmouth South (again available from the SRS website at https://www.s-r-s.org.uk/html/gwu/S3224.htm) show:

 

Quote

Regulation 4A

The Up Distant Signal for Barmouth North signal box being permanently fixed at Caution, this Regulation will not apply to the acceptance of Up trains."

 

This would seem logical for the situation where Truro East had a full clearing point available but did not have line clear through to the next box east.  Truro West's Distant would then effectively act as an additional fixed distant for East giving 922 yards to Truro East Up Main Home (This is however still less than the 1000 yards shown in the book for a falling gradient but the severe 15 mph PROS through the Up Platform may have been taken in account).  This would then avoid the seemingly unsatisfactory situation of a West having to maintain the Up Home at danger and the driver seeing it after having previously not been cautioned at Penwithers Junction.

 

The problem here though is if regulation 4A was used for the purposes of allowing East to accept a train without having the full clearing point available (which was suggested above would have been the case if modified clearing points were not used).  This I believe would require the train to be cautioned at Truro West and I can't see any way of doing this if the driver sees a cleared distant at Penwithers Junction (West having accepted under regulation 4).  Unless of course West did indeed maintain their Up Home at danger until the driver saw it after emerging from the tunnel but I feel very uncomfortable about that situation.

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8 hours ago, Mark Saunders said:

Bedlington South’s Down Section and Bedlington North’s Distant less than 300yardsto to the Home board!

818D9082-FEC6-4679-942D-73E1302658B9.png

I don't think any special provisions apply. Bedlington South's home signal is almost certainly more than 440 yards from Bedlington North's home signal, so it doesn't fall within the provision for short sections within Regulation 4, and Regulation 4A didn't apply outside the Western Region.

 

Bedlington North's distant is fixed, as you can see (so, for that matter, is Bedlington South's). Bedlington North's home signal is presumably visible from Bedlington South box, so perhaps the Bedlington South signalman cautions trains if he can see that Bedlington North home is at danger. But this is probably unnecessary since I imagine that speeds are low.

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20 minutes ago, Jeremy Cumberland said:

I don't think any special provisions apply. Bedlington South's home signal is almost certainly more than 440 yards from Bedlington North's home signal, so it doesn't fall within the provision for short sections within Regulation 4, and Regulation 4A didn't apply outside the Western Region.

 

Bedlington North's distant is fixed, as you can see (so, for that matter, is Bedlington South's). Bedlington North's home signal is presumably visible from Bedlington South box, so perhaps the Bedlington South signalman cautions trains if he can see that Bedlington North home is at danger. But this is probably unnecessary since I imagine that speeds are low.

 

Reg 4A was only ever in the GWR and BR(WR) block regulations - it never applied to other companies.  One peculiarity of the NER was that whilst the clearing point for acceptance of trains on most railways was an overlap of 440 yards from Home Signal, but originally was only 400 yards on the NER (later brought in line with the rest of the country).  Distant signals in most places were usually much further from the home than that though - often over 1000 yards; line speed and gradient always being factors.  The Reg 4A problem was more to do with braking distances on higher speed lines than places like Bedlington which was a relatively minor freight route in a coal mining area.

 

It is often fairly hard to tell from a photo whether a distant is fixed or working because you generally can't see operating wires clearly.  Here the clues are more obvious - the absence of a green spectacle (because it's not needed) and the absence of  the three counterweights generally to be found to slot a home and distant on the same post.

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18 hours ago, Zoe said:

The box instructions for Barmouth South (again available from the SRS website at https://www.s-r-s.org.uk/html/gwu/S3224.htm) show:

 

 

This would seem logical for the situation where Truro East had a full clearing point available but did not have line clear through to the next box east.  Truro West's Distant would then effectively act as an additional fixed distant for East giving 922 yards to Truro East Up Main Home (This is however still less than the 1000 yards shown in the book for a falling gradient but the severe 15 mph PROS through the Up Platform may have been taken in account).  This would then avoid the seemingly unsatisfactory situation of a West having to maintain the Up Home at danger and the driver seeing it after having previously not been cautioned at Penwithers Junction.

 

The problem here though is if regulation 4A was used for the purposes of allowing East to accept a train without having the full clearing point available (which was suggested above would have been the case if modified clearing points were not used).  This I believe would require the train to be cautioned at Truro West and I can't see any way of doing this if the driver sees a cleared distant at Penwithers Junction (West having accepted under regulation 4).  Unless of course West did indeed maintain their Up Home at danger until the driver saw it after emerging from the tunnel but I feel very uncomfortable about that situation.

If East accepted an Up train from West under 4A then West would, in view of the tunnel, have possibly maintained his Home Signal at danger until the train was approaching it as 4A required him to do however the 15 ph PROS on the Up Main would have presented no problem if had cleared the signal earlier becaus the train would be approaching at low speed. The situation is however complicated to the extent that if East accepts under 4A how would West accept from Penwithers Jcn and here we come back to a potential Modified Clearing Point or any amendment to he Regulation itself.  

 

Note that in the Down direction West's Station Limits weren't much over 200 yards in total hence a normal full Clearing Point would have been in the section in advance (and it might well have been - for all we know at this late remove).  The problem with everything at Truro is that it is clear that the low permitted speeds would have had an impact and would have affected what was on the 'box Instructions.  Don't forget also that although the Regulatios were standard there might well have been a degree of interpretation between offices which would take into account the view of the local Inspectorate when framing 'box Instructions.  

 

We (I) know that such differences definitely existed between WR Divisions as late as the 1970s and what happened in respect of certain things in the Cardiff Division was not treated in the same way in the Bristol Division as I found when I moved from one to the other.   I  the ended up asking for various alterations to be made to the 'box Instructions at 6 of my 'boxes to bring them into line with either specific parts of the Regulations or to provide for additional things such as route detailing bell codes.  And even as late as the mid 1980s, after the job was concentrated at Regional level and when i was in charge of the post dealing with 'Box Instructions, we were  still finding some differences in wording between 'box Instructions that had been produced in the different Divisions.  

 

And don't forget that there could be an element of need for interpretation of the exact meaning of particular Rules and Regulations.  At one time I was the WR's person who answered any questions regarding interpretation.  While they were few and far between they could be amusing - the best example being the Signalman at Moreton-In-Marsh who rang in one day to ask if, in the meaning of the Regulation, a wallaby was a large animal because one had escaped from some sort of safari park style attraction not far from the line. (The meaning of 'large' at that time was an animal of sufficient size to derail a train if it was hit by one).

 

If you want a really interesting example of acceptances the Up Main Platform Line at Reading is probably the ultimate.  It lay in one of the sections between Reading Main Line West and Reading Main Line East and Shunting into Forward Section was permitted at Main Line West.  Apart from that Main Line East could accept trains under Full Line Clear, under Regulation 4A ,  or Passenger trains only under Regulation 5. or accept a second train into the Section under Permissive Regulations.  The Section Signal at Main Line West could show 4 different proceed indications - the running arm or any one of all three subsidiary indications

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