Black Country Blues

[2ManySpams]

Bingo! You've already done it.... Just as long as no one mentions anything along the lines of a receptacle for pouring gravy out of....

 

Saucepan? Gravy Boat? Bucket?

[Indomitable026]

Bingo! You've already done it.... Just as long as no one mentions anything along the lines of a receptacle for pouring gravy out of....

Or 'Churns'

[2ManySpams]

That's it then, Permissive Block working it is then..... (Opens up new spam  can of worms and runs for cover!  )

 

Perhaps we should let them run a steam tour behind a Black Five first?  Seems more appropriate. (Not that I have anything against Spam Cans).

 

Ok then, for signalling thickies like me - what is Permissive Block working and what visible difference would it make to a modelled scene??

[gwrrob]

Soon no layout will be safe (maniacal laugh) 

 

Does that include mine oh master.

[Fat Controller]

Ok then, for signalling thickies like me - what is Permissive Block working and what visible difference would it make to a modelled scene??

Until one of the signalling experts comes along, this is my understanding:-

Under normal block operation, no train may enter a signalled section until the previous train has cleared it.

Under permissive block working, a second train may enter a block section, at such a speed that it can stop short of the train in front; if there is still space behind the last vehicle and the signal at the rear of the section, then a further train may enter. As far as I'm aware, there are two circumstances where it would be used:-

At stations where trains divide and attach portions.

On goods-only lines, where trains might be waiting for an onward path through a station or junction; into the 1960s/early'70s, it was quite common to see goods trains lined up like this in some areas.

The difference that would be evident on a model would be that the first train would be stopped at a signal; the second train would be stopped just short of the last vehicle of the first and so on. Speeds should be not much more than walking pace, though different drivers would interpret that differently.

Edited October 23, 2013 by Fat Controller

[Andy Y]

Oh dear; I've gone all funny.

 

 

A big +1 for Mark's signal box, loco and rolling stock.

[gwrrob]

'Oh dear; I've gone all funny.'

 

 

No I call that arty.Superb.

[BlackRat]

It seems that the Leicestershire strategic reserve of Spamcans need narrow gauge track so it looks like Darlo is safe for now. Previous outings have shown how good it looks with a dirty 8F on it; maybe we could rustle something up for the end of the day at a yet to be announced date for the layout?

Couldn't you add washers to the wheels..........you know, sort of pad them out a bit?

 

And for this permissive stuff, don't Noch make some naughty permissive scenes?

Edited October 23, 2013 by BlackRat

[The Stationmaster]

Ok then, for signalling thickies like me - what is Permissive Block working and what visible difference would it make to a modelled scene??

I suspect - without doing any delving at this stage - that it would probably have remained as Absolute Block unless there was any saving in converting it to Permissive or there was actually the money available to convert it (which basically would mean changing the block instruments although the LM might also have been careful about signals which were not quite in the right place in respect of pointwork they were protecting).

 

So to begin at the beginning - the line would have originally have been Absolute Block which means that only one train is allowed in a block section between the most advanced stop signal of the signalbox at the rear end of the section (the Section Signal in fairly modern parlance) and the outermost Home Signal of the signalbox at the advance end of the section.  In addition unless any particular arrangements were in place to permit a change only one train is allowed in every signal section (i.e. the section of line between two successive stop signals including those stop signals worked from the same signalbox).

 

In the light of early experience the Absolute Block system also required a Clearing Point at the signalbox at the advance end of the block section and for many years on double (& multiple) line Absolute block working this clearing Point was 440 yards - in some circumstances it is still 440 yards today.  The Clearing Point extends for 440 yards in advance of the outermost Home Signal and is basically a safety margin - to accept a train the Signalman must ensure that 440 yards is clear and that all points are correctly set for the train he is going to accept and once he has accepted a train he is not permitted to foul/use that Clearing Point for anything else - like letting a train out of a yard straight through it.  He is permitted to foul the Clearing Point however if the train he has accepted is cancelled (3-5 bell signal, remember it as 'not going', 3 letters followed by 5) or if the train has been brought to a stand at the Home Signal.  (Hence what I picked up in the original pics where the train with the Class 24 clearly had not arrived at the Home Signal).

 

In the model world the Clearing Point has usually to be selectively compressed and in the real world you can sometimes come across a Modified Clearing Point where authority has been given for it to be reduced for some reason.

 

The Absolute Block Regulations also include a wizard wheeze called 'the warning (formerly Absolute Block Regulation 5, ABR 5) where in certain circumstances the normal Clearing Point may be dispensed with and a train can be accepted if the line is only clear as far as the Home Signal itself.  The main reason for permitting Warning Acceptance was to try and keep trains moving - albeit Drivers should reduce speed having been accepted in that manner - in areas of considerable traffic density such as the approaches to a major station.  It would require some very special circumstances, and a lot of convincing of those responsible for agreeing it, to have it at some ordinary wayside signalbox on a relatively lightly trafficked line although it wasn't impossible but in agreeing it those who were responsible would pay very careful attention to things like gradients, signal position and so on let alone the reason why it was being sought  By the 1970s, with traffic levels declining it was more likely to be taken away from those places which had it rather than be given to anywhere new and there were very mixed views about its retention (the LMR in particular was at one time very strongly in favour of abolishing it - they finally won).  I would consider the use of ABR 5 to be very unlikely for any trains coming towards BCB - i would need to study the setting and traffic to see if any adjacent 'boxes might have had it.

 

Right back to the question.  Absolute Block is great where the frequency of signalboxes allows the level of traffic to flow reasonably smoothly but on heavily used goods lines it can be inadequate for the number of trains and it can also be inadequate at stations where platforms need to be used by more than one train.  So there was an alternative and that was called Permissive Block and it allowed more than one train to be in a block section at a time but the penalty was a very severe restriction of speed to, for example, a maximum of no more than 10 or 15 mph for all trains at all times irrespective of what was ahead of them.  And the only way to separate them from what was ahead of them was the Driver of a following train coming across the brakevan and tail lamp of the train ahead.

 

So while it increased line capacity in one way it effectively reduced it in another by requiring lower speeds which lengthened running times reducing operational efficiency.  But in, say, the approaches to a busy yard or where there was a lot of already slow moving freight traffic it had the advantage of allowing trains to queue in a section instead of sitting at the signalbox in the rear waiting Line Clear when the train in front cleared the section.  Another advantage it had - very pertinent here - is that trains could be accepted if the line was clear only to the Home Signal.

 

A quick cast through the 1975 Sectional Appendix reveals nothing in the way of traditional (goods) Permissive Block in the Birmingham area but there were a couple of places where Absolute Block was used on goods lines.  There were some lines - not surprisingly, see my earlier comments - where goods permissive working was used on colour light signalled lines worked iunder track Circuit Block Regs but they were where traffic would be heavy.

 

Overall my view is that the BCB line would be worked by Absolute Block and if it was me there's no way I could find any reason to suggest recommend a relaxation to allow ABR 5 acceptances - the traffic level doesn't warrant it and the siting of the Home Signal in relation to the single slip would - in modern terminology - present too high a level of risk (which in reality is a fancily worded way of saying 'it's not on mate'.

 

Answering Chris' original question about the difference it would make to the modelled scene the answer is 'very little' - but it would or could make an observable difference to the way trains are worked - especially if they are running towards the Home Signals when there patently isn't a Clearing Point, even a selectively compressed one.

 

If in doubt on any of the above points please ask.

Edited October 23, 2013 by The Stationmaster

[Oldddudders]

SM at his brilliant best!

[gwrrob]

SM at his brilliant best!

 

That's what we pay him for !

[2ManySpams]

Smashing answer Mike - you're not going to test us all now are you?

[wagonbasher]

I have to take exception..... Could the 24 have stopped, but pulled up short, maybe new brake shoes or a new pair of boots?

 

Seriously. Can we fetch the twenties out as long as the 24 has pulled up at the off (or is it on / the time when the signal arm is horizontal) signal and presumably the bobby has seen him stop. Or would they have simply waited until there was a gap in the traffic.

 

andy

[TheSignalEngineer]

Great answer as usual from SM.

 

By the end of the 1960s there was very little semaphore signalling on the ex-LNW lines of the Birmingham Division. From memory I would say it was limited to the South Staffs lines from Dudley to Wednesbury, Rushall to Lichfield TV junction and Bloxwich to Cannock, the Cannock Mineral Railway from Cannock to Rugeley, the Princes End Branch from Wednesbury to Tipton Curve Junction, Erdington to Lichfield City, Milverton to Gibbet Hill and Coundon Road to Griff Junction (Nuneaton). All had carried regular passenger services although the Princes End Branch lost its two stations in 1916 as a wartime economy measure. Only the Erdington to Lichfield line had a passenger service by then, but the rest were still used for dated passenger trains and excursions (even an instance in the 1960s of Spamcan 79 via Princes End, cue for Chris), or as diversionary routes for engineering work. Consequently all had historically been worked under Absolute Block Regulations.

 

At most boxes the first home signal was quite close to the first set of points, so few had a 440 yard acceptance point which was free from possible obstruction. Generally if this was to be achieved an Outer Home was provided. In reality most of the Block sections were so short there wasn't room for this. Distants under Starters were far more common. Placing the Home signal on BCB at the clearance point of the crossover would have been quite prototypical.

 

Regarding ABR 5, I can't remember any particular instances of it being authorised, in fact I think there was an exercise around that time to get rid of any remaining instances which may have lurked in box instructions.

[andymozza]

Great answer as usual from SM.

 

By the end of the 1960s there was very little semaphore signalling on the ex-LNW lines of the Birmingham Division. From memory I would say it was limited to the South Staffs lines from Dudley to Wednesbury, Rushall to Lichfield TV junction and Bloxwich to Cannock, the Cannock Mineral Railway from Cannock to Rugeley, the Princes End Branch from Wednesbury to Tipton Curve Junction, Erdington to Lichfield City, Milverton to Gibbet Hill and Coundon Road to Griff Junction (Nuneaton). All had carried regular passenger services although the Princes End Branch lost its two stations in 1916 as a wartime economy measure. Only the Erdington to Lichfield line had a passenger service by then, but the rest were still used for dated passenger trains and excursions (even an instance in the 1960s of Spamcan 79 via Princes End, cue for Chris), or as diversionary routes for engineering work. Consequently all had historically been worked under Absolute Block Regulations.

 

At most boxes the first home signal was quite close to the first set of points, so few had a 440 yard acceptance point which was free from possible obstruction. Generally if this was to be achieved an Outer Home was provided. In reality most of the Block sections were so short there wasn't room for this. Distants under Starters were far more common. Placing the Home signal on BCB at the clearance point of the crossover would have been quite prototypical.

 

Regarding ABR 5, I can't remember any particular instances of it being authorised, in fact I think there was an exercise around that time to get rid of any remaining instances which may have lurked in box instructions.

Hi all, back in the mid 70's I spent an awful lot of my pre-teenage evenings in the boxes at Round Oak and Kingswinford Jct (Brierley Hill). Rule 5, warning Arrangement, bell code 3-5-5 was in use at both boxes in both directions, however it was not allowed southbound from KJ to Stourbridge Jct. North box, where passenger trains came in from the Brum Line. It was quite common around 7.30 ish for the down 4S88 pengam- edinboro FLT to be green flagged at SJN if the evening Bescot trip T57 had been backed out across the main at KJ when offered. Likewise if T57 was calling at Round Oak and had to back in, 4S88 would be green flagged at KJ. it was my interpretation that rule 5 was available at most locations on freight only lines using absolute block. cheers Andy.

[The Stationmaster]

Smashing answer Mike - you're not going to test us all now are you?

I have already sent the test paper to one aspirant

[Stubby47]

Going back to the photos that caused all this, would the 20s have had to stay in the yard until the 24 arrived at the Home signal, even if this meant a long wait - I'm assuming that if the 24 was in the section, the answer would be Yes, but if there was no train in the section, then none would have been allowed in until the 20s had clearwd the crossing ?

[The Stationmaster]

Going back to the photos that caused all this, would the 20s have had to stay in the yard until the 24 arrived at the Home signal, even if this meant a long wait - I'm assuming that if the 24 was in the section, the answer would be Yes, but if there was no train in the section, then none would have been allowed in until the 20s had clearwd the crossing ?

Yes Stu -it's all a matter of timing.  If the Signalman has accepted the train with the 24 on he can't then swing the road for the other one to leave the yard until the 24 has stopped at his Home Signal, if he has the road set for the other one to leave the yard then he can't accept the one with the 24 on until the one from the yard is clear of the crossover.

 

While folk could get caught out by all sorts of things unexpectedly happening normally the Signalman would know what trains are where and plan and regulate accordingly so delays would be avoided.  But if one of the trains was late for some reason he might might have to take a different tack and cause it, perhaps, to be even later in order to keep the other one on time.

 

And in busier places - if the length of sections allowed there could well be an additional Home Signal at least 440 yards from the one protecting the points in order to create a Clearing Point while a train was crossing from the yard.  But we're not looking at a place which is that busy.

[TheSignalEngineer]

Hi all, back in the mid 70's I spent an awful lot of my pre-teenage evenings in the boxes at Round Oak and Kingswinford Jct (Brierley Hill). Rule 5, warning Arrangement, bell code 3-5-5 was in use at both boxes in both directions, however it was not allowed southbound from KJ to Stourbridge Jct. North box, where passenger trains came in from the Brum Line. It was quite common around 7.30 ish for the down 4S88 pengam- edinboro FLT to be green flagged at SJN if the evening Bescot trip T57 had been backed out across the main at KJ when offered. Likewise if T57 was calling at Round Oak and had to back in, 4S88 would be green flagged at KJ. it was my interpretation that rule 5 was available at most locations on freight only lines using absolute block. cheers Andy.

Prior to resignalling for electrification, ABR 5 was quite common at boxes on the LNW lines. Most had sidings where trip workings shunted. Freights would commonly be accepted "under the Warning" when a shunt was in progress. By 1967 most of the LNW lines were MAS, and the box instructions had to be re-written at the fringe boxes so there were few boxes left that were pure Absolute Block. As local freight traffic declined box closures were taking place at a rapid rate, especially during 1969-73 under the 'Surplus Capacity' schemes resulting from grants under the 1968 Transport Act. Each time the instructions at boxes either side were reviewed and often revised. I can't remember off-hand whether ABR 5 was specifically allowed or specifically excluded from box instructions in those days, perhaps Mike could tell us?

 

The Stourbridge Junction to Dudley section was part of the GWR, and probably one of the last bits of the Birmingham Division where ABR 5 was regularly used, particularly after Stourbridge Engine Shed box was closed. Traffic would sometimes get clogged up at Stourbridge Junction, so it was necessary to get rid of a train towards Dudley. Stourbridge Junction North was closed in the late 1970s in December 1973, and the signalling there was replaced by colour lights controlled from the Middle box.

Edited October 24, 2013 by TheSignalEngineer

[andymozza]

Prior to resignalling for electrification, ABR 5 was quite common at boxes on the LNW lines. Most had sidings where trip workings shunted. Freights would commonly be accepted "under the Warning" when a shunt was in progress. By 1967 most of the LNW lines were MAS, and the box instructions had to be re-written at the fringe boxes so there were few boxes left that were pure Absolute Block. As local freight traffic declined box closures were taking place at a rapid rate, especially during 1969-73 under the 'Surplus Capacity' schemes resulting from grants under the 1968 Transport Act. Each time the instructions at boxes either side were reviewed and often revised. I can't remember off-hand whether ABR 5 was specifically allowed or specifically excluded from box instructions in those days, perhaps Mike could tell us?

 

The Stourbridge Junction to Dudley section was part of the GWR, and probably one of the last bits of the Birmingham Division where ABR 5 was regularly used, particularly after Stourbridge Engine Shed box was closed. Traffic would sometimes get clogged up at Stourbridge Junction, so it was necessary to get rid of a train towards Dudley. Stourbridge Junction North was closed in December 1973, and the signalling there was replaced by colour lights controlled from the Middle box.

Hi, I think you will find it was Stourbridge Jct South that closed in 73, the North box in 76, Andy.

[beast66606]

Prior to resignalling for electrification, ABR 5 was quite common at boxes on the LNW lines. Most had sidings where trip workings shunted. Freights would commonly be accepted "under the Warning" when a shunt was in progress. By 1967 most of the LNW lines were MAS, and the box instructions had to be re-written at the fringe boxes so there were few boxes left that were pure Absolute Block. As local freight traffic declined box closures were taking place at a rapid rate, especially during 1969-73 under the 'Surplus Capacity' schemes resulting from grants under the 1968 Transport Act. Each time the instructions at boxes either side were reviewed and often revised. I can't remember off-hand whether ABR 5 was specifically allowed or specifically excluded from box instructions in those days, perhaps Mike could tell us?

 

 

Reg 5 was authorised for goods to goods at a lot of places (at that time), with similar layouts / needs -  certainly on "my" patch.

On a goods only line it wouldn't be a problem, in fact running a passenger would be more of a problem as Reg 4 would possibly have to be implemented if permissive was in use.

 

 

Edited to correct the rubbish I posted earlier - I blame a three hour drive.

[Stubby47]

So as well as the loco cards, should BCB operators also be showing the appropriate Regulation, sub-clause, local standing instructions and parish news applicable at the time whenever they move a loco out of the fiddle yard ?

[The Stationmaster]

So as well as the loco cards, should BCB operators also be showing the appropriate Regulation, sub-clause, local standing instructions and parish news applicable at the time whenever they move a loco out of the fiddle yard ?

It depends what folk want the layout to do Stu.  In my view if it looks the part (which it does) it should be worked to the same level of 'reality' or it is going to do something to damage its own image with those who appreciate it but understand the real thing.  OK there might not be too many of us in that latter category but i don't see why that number shouldn't gradually increase as folk gain a broader knowledge of all the elements which go into their hobby - so people enjoy creating things, some like modelling railways, some like playing trains, and so on.

 

The visual and 'atmospheric' category where BCB lies is very very clear in my mind and I see no reason why it can't become a wider trend setter, after all a lot of trouble is being taken to turn the trains from a collection of wagons into wagons working believable traffic flows and worked by credible locos for time and place (most of the time ).  Having got all that as 'right' as possible it seems to me to be missing something not to go all the way on other things too - but in the end that's up to the guys who put it together.

 

Incidentally as far as ABReg 5 was concerned it could only be used where specially authorised, in writing, in the Signalbox Instructions and if they found it to be in regular use the MoT (formerly BoT) HMRI inspectorate would require the railway to provide proper subsidiary signals although it did not require their agreement to use it.  There was for many years a debate within the railway community as to whether or not it was to be considered a safe method of working with one camp maintaining that it wasn't because the 440 yard Clearing point was being dispensed with and the other camp maintaining that in fact it was much safer because a Driver had been informed, long before he reached it, that the signal would be at danger.  I'm not sure who won that one but as I've already said by the 1970s some parts of BR were far from keen on keeping the Regulation.

[avonside1563]

Oh heck, we're all going to be victims of our own success.... prototypical operation now is it? Hope the public don't mind standing in front of the layout waiting for the next train to arrive!

[Oldddudders]

Hope the public don't mind standing in front of the layout waiting for the next train to arrive!

Interesting conceptual point. The "moves" that Andy Y juxtaposed, and which started this valuable debate, if they had actually happened would have looked really attractive to the average punter - but be dead wrong in reality. One train doing this, another creeping up and waiting the road etc. The BCB team needs to consider whether always doing things according to the book will compromise some of the visual operating appeal at exhibitions to the large % of punters who are not aware of the rules and regs. As one who firmly believes that there should be something moving as often as possible I see the scope for occasional conflicts here.