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Complex block sections


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Bit of a "complex" railway question: In the world of UK Absolute block system - what's the largest number of adjoining block sections there has been on the uk rail network? Hamlyn, below, obviously has 3, but I can imagine there are other blocks with a few/lot more 'neighbours'?

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Well I would say box above has 6 sections - 3 pegging instruments from the box in rear and 3 non-peggers to the box in advance.

And you have twice as many sections on a four-track line without increasing the number of junction.

 

If you take a station like Lincoln, in one direction Pelham Street box had instruments for each of the through platforms as well as the non-platform through roads to High Street and to two routes in the other, so the block shelf was very full.  And that was after St Marks station had closed and lifted.  A really big station like Rugby had as many as 7 boxes, so there would be a lot of instruments from one of these to another, but although there were routes to quite a lot of places from the town the junctions were signalled from separate boxes.   When power signalling came in a place like Crewe lost a lot of smaller boxes and Crewe North and South boxes then controlled larger areas.

 

By contrast a big seaside terminus like Lowestoft has a thundering great lever frame and a very long block shelf carrying a single Up/Down combined instrument.  

 

 

Edited by Michael Hodgson
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And then you need to consider boxes that switch out. Back in the day, Williton on the Minehead branch worked to both crowcombe and Leigh bridge in the up direction and Blue Anchor or Kentsford in the down. This was a single line so four sets of token instruments.

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Norton Fitzwarren. Had the following:

Double line to Milverton

Double line to Bishops Lydeard

Double line to Victory crossing

Down loop to Victory crossing

Quadruple track to Silk Mill.

So I think that means six sets of block instruments and bells....

 

 

 

 

 

 

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On 23/02/2021 at 16:08, Philipe said:

Interesting - Hadn't even thought about four-track lines.

 

Or six and eight track lines. Saltley Junction had six to Saltley Sidings and eight to Duddeston Road.

Nearby, Grand Junction had 4 to Proof House, 2 to Curzon Street No.1, 4 to Exchange Sidings and 2 to Landor Street. 

Proof House Junction had 4 to Grand  Junction and 2 each to New Street No.1, New Street No.2, Curzon Street No.1 and Vauxhall.

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Exeter West had 6 I think:

Main, Relief and Southern to Middle box 

Southern to Central B box

Main to City Basin box

Goods to Goods box

Paul.

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Or for a really big number, Bristol East power frame:

Up & Dn Main and Up Relief to North Somerset Jn

Up & Dn S Wales Main and Relief to Dr Days Jn

Up & Dn Old Station to Old Station box

Engine Road to Loco Yard box

and 5 pairs of lines to West Jn.

That could be 11 instruments!

Paul.

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Old Oak Common East didn't do too badly =

 

Absolute Block

Up&Down Mains from Ladbroke Grove, 

Up&Down Reliefs from Ladbroke Grove,

Victoria Branch to North Pole Jcn,

Up&Down Mains to OOC West,

Up&Down Reliefs to OOC West  

=5 double line block instruments

 

Permissive Block

Up & Down E&C from Ladbroke Grove  (These might have been some form of TCB, I'm not absolutely sure on that but they were continuously track circuited and subject to special Instructions)

Up&Down Goods from Ladbroke Grove.

Down Main Goods Loop from Ladbroke Grove

Down Goods to OOC West

Up&Down Engine Lines to OOC Loco Yard 'box

= a minimum of 6 Permissive Block instruments (excluding the E&C lines)

 

11 block instruments in total, 8 pegging.

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Just round the corner from Bristol East I think North Somerset Junction must have had quite a few at one time.

I am no signalling expert but looking at the layout on an old 25in map there are a lot of lines.

Is it

3 lines to/from Bristol East 

4 lines to/from Dr Days Junction

2 lines to/from Marsh Junction

4 running lines to/from East Depot. Would the loop/departure roads from East Depot Downside also count?

 

cheers 

 

 

cheers

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Reading Main Line East was interesting because of the additional Absolute Block lines it had.

 

Up&Down Mains from Kennet Bridge,

U&Down Reliefs from Kennet Bridge

Up&Down Branch from Reading Spur,

Up & Down Loops from Reading Spur,

Additional Down Loop from Reading Spur

Up&Down Branch from Reading Junction (SR)

Up&Down Mains to Reading Main line West

Additional Up Main Platform Line to Reading Main Line West 

Up & Down Reliefs to Reading Main Line West

 

All the above were Absolute Block = 9 block instruments and 9 pegging blocks

Plus Permissive Block on the Up&Down Goods to Reading West goods = total  11 block instruments and 10 pegging blocks.

 

And just to add interest on some blocks it could accept trains under several different conditions which meant different Acceptance Bell Signals from a straight repetition.

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On 23/02/2021 at 16:13, ikcdab said:

And then you need to consider boxes that switch out. Back in the day, Williton on the Minehead branch worked to both crowcombe and Leigh bridge in the up direction and Blue Anchor or Kentsford in the down. This was a single line so four sets of token instruments.

Not entirely true IMHO. In the Down direction Williton used to work short section to Kentsford or long section to Washford. After Washford was abolished in 1952 the 'switching out' facility at Kentsford was removed...as noted on p102 of a certain book :-):-)

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Whether an intermediate box switches out or not is irrelevant to how many sections are controlled by adjacent signal boxes.  If intermediate signal boxes are switched out, the block sections are merely lengthened, not doubled.  The number of sections remains the same except when the closure of a box shuts a running line completely such as any running line that terminates at the closing box.

 

It is also misleading to simply count the instruments as they can be single or combined units.  The best way of counting the block sections is to count the number of needles (or whatever other type of indicator is used).  However this isn’t perfect either as some non-passenger lines can be worked on various forms of the 'No Block' system but these are definitely still regarded as block sections!

 

Also, in my opinion a single or bi-directional line should always count twice.  A single line terminus with conventional block instruments would be provided with two needles; one for the up and one for the down.

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2 hours ago, ReTyerd Signalman said:

Also, in my opinion a single or bi-directional line should always count twice.  A single line terminus with conventional block instruments would be provided with two needles; one for the up and one for the down.

I'm afraid that I fail to understand the logic for that approach. If you have a single line between A and B then IMHO that is one block section, regardless of whether it is uni- or bi- directional and the type and number of 'instruments' that may be used to control it.

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4 hours ago, RailWest said:

I'm afraid that I fail to understand the logic for that approach. If you have a single line between A and B then IMHO that is one block section, regardless of whether it is uni- or bi- directional and the type and number of 'instruments' that may be used to control it.

My logic is that a block section starts at the section signal in rear and ends at the outermost home signal at the box in advance.  The up and down sections of a single line rarely coincide.  The sections overlap but have different limiting points depending on the location of the signals.  In that respect the sections in opposing directions can be very different.

 

A block section is always deemed to be under the control of the accepting signalman in advance.  A single or bi-directional line is therefore under the control of a different signalman depending on which direction it is being used for.  If a train is proceeding from A to B it is signalled on the block instrument controlled by B but the signalman at A is still permitted to shunt a train into his rear section. If the other train clears the section he blocks back on his own instrument.  Both signalmen can also block back outside the their home signals at the same time.  It is therefore possible and perfectly within the rules for a single line to be occupied at both ends by trains on both the up and down instruments.  Some people would count that as two block sections while others are counting a double line as only one section.  It is all a matter of opinion.

 

Sorry if I’m confusing some people but I was just trying to point out that unless everyone uses the same method as each other, comparisons can’t really be made.  When it comes to ‘Track Circuit Block' you can have numerous sections in one direction but only one in the other.  How do you count those?
 

 

Edited by ReTyerd Signalman
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My word this is getting barmy.  As far as the Single Line Block Regulations (for traditional methods of signalling) are concerned the critical signals are the Home Signal and the Section Signal but in some Regulations the Section Signal is irrelevant and the only signal which matters as far as the Regulation is concerned is the Home Signal.  If a Signalman is unable to keep track of what is happening in a single line section from a Train Register Book using double line block instruments is hardly going to help.

 

However interestingly there was of course the situation in the Regulations that where 'ordinary' double line block instruments were used for single line signalling where there was one circumstance where the Signalmen at both ends of the section could place their instrument to the 'Train On Line' position and taht was if a shunt was being made into both ends of the section.  The rest of the time the instruments were worked in the normal manner in respect of any train movement between teh two 'boxes concerned.

 

I'm sure that from his past experience 'ReTyred Signalman' will know what that situation was and be able to quote the Regulations involved.  PS although it may be obvious to some it might not be to everybody so it would help if he could also explain why ordinary double line block instruments were used on a single line.

 

Edited by The Stationmaster
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6 minutes ago, The Stationmaster said:

My word this is getting barmy....

 

To be honest, that sums up my thoughts too :-)  Perhaps this has become a case of 'over analysing' what was otherwise quite a simple question.

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21 minutes ago, RailWest said:

To be honest, that sums up my thoughts too :-)  Perhaps this has become a case of 'over analysing' what was otherwise quite a simple question.

I quite agree but the subject title is appropriate!  I think I could have explained things a little easier.

In my opinion a block section only exists in one direction.  If a train enters a single line and stops half way, any change of direction is regarded as a wrong direction move.  This applies to all single or bi-directional lines except those worked by ‘One Engine in Steam' or modern equivalent.

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1 hour ago, ReTyerd Signalman said:

I quite agree but the subject title is appropriate!  I think I could have explained things a little easier.

In my opinion a block section only exists in one direction.  If a train enters a single line and stops half way, any change of direction is regarded as a wrong direction move.  This applies to all single or bi-directional lines except those worked by ‘One Engine in Steam' or modern equivalent.

Perhaps you could also answer my question regarding the use of ordinary double line block instruments on a single line.  Perhaps you could remind where in the Rule & Regs there is a reference to wrong direcxtion moves on single line as I can't currently find the reference?

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4 minutes ago, The Stationmaster said:

Perhaps you could also answer my question regarding the use of ordinary double line block instruments on a single line.  Perhaps you could remind where in the Rule & Regs there is a reference to wrong direcxtion moves on single line as I can't currently find the reference?

Sorry.  I misread your post and didn’t realise you were asking me a direct question.

 

I was referring to 'Staff and Ticket' working.  To those not familiar, a single line is worked by ordinary block instruments the same as used on a double line.  Security is obtained by using a train staff for alternate up and down working but tickets can be issued by the signalman who has the staff if consecutive trains are to travel in the same direction.  The staff being carried through the section by the driver of the last train before a train in the opposite direction.  All works well until the forward planning falls apart!

 

 I don’t have my Rules or Regs books so I cannot quote from them.  I think I may have had a brief ‘senior moment' by quoting single lines and got a bit muddled with bi-directional permissive working.  Apologies for any confusion.  Brain-fade is becoming far too regular!

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56 minutes ago, ReTyerd Signalman said:

Sorry.  I misread your post and didn’t realise you were asking me a direct question.

 

I was referring to 'Staff and Ticket' working.  To those not familiar, a single line is worked by ordinary block instruments the same as used on a double line.  Security is obtained by using a train staff for alternate up and down working but tickets can be issued by the signalman who has the staff if consecutive trains are to travel in the same direction.  The staff being carried through the section by the driver of the last train before a train in the opposite direction.  All works well until the forward planning falls apart!

 

 I don’t have my Rules or Regs books so I cannot quote from them.  I think I may have had a brief ‘senior moment' by quoting single lines and got a bit muddled with bi-directional permissive working.  Apologies for any confusion.  Brain-fade is becoming far too regular!

Always very sensible to carefully check stuff before posting about anything in cnnection with things like Rule and Regulations or working methods.  Many members of RMweb aren't at all familiar with the real railway, especially the past real railway, and it is all too easty for them to be misled if stuff is posted without first checking (or quoting the relevant dates).

 

Anyway why would ordinary double block instruments be used with TS & T working as they do absolutely nothing to prevent trains being signalled in opposite directions overa. single line?

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4 minutes ago, The Stationmaster said:

Anyway why would ordinary double block instruments be used with TS & T working as they do absolutely nothing to prevent trains being signalled in opposite directions overa. single line?

I guess before Mr Tyer invented his tablet system there was nothing better.  After that many railways just didn’t want to spend money!

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