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Engineering possessions on AB lines

You are here: Home > Forum > Miscellaneous > The real thing (signalling) > Engineering possessions on AB lines

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Engineering possessions on AB lines 15/11/2021 at 16:38 #142341
Steamer
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I got thinking about engineering possessions recently, and how they're handled on AB lines. Are there a set of bell codes used to signify possessions are being taken in the block section? I've never seen them listed in tables of codes, but it seems an odd thing not to have covered. Also, what decides which box "leads" the giving and cancelling of a line block?
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Engineering possessions on AB lines 15/11/2021 at 17:02 #142342
TUT
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Quote:
Are there a set of bell codes used to signify possessions are being taken in the block section?
Yes there are now: block line for protection purposes (2-2-2) and line block completed (1-2-2)

Quote:
Also, what decides which box "leads" the giving and cancelling of a line block?
Both of these bell signals must always be sent forward.

In the case of a line blockage, in principle the COSS(/IWA/PC/SWL) could phone either signal box. If you are the box in rear you would contact the box in advance and after explaining the circumstances and coming to a clear understanding, as long as the block is normal (there is an exception), send 2-2-2 forwards. This would be acknowledged and the box in advance would peg train on line. If you are the box in advance you would contact the box in rear, explain the circumstances and they would then send you 2-2-2. 2-2-2 is always sent forwards. Same with 1-2-2.

With a possession, the PICOP will contact the signaller who controls a protecting signal. If you had a mega possession involving say four boxes - A, B, C, and D - the PICOP will only phone A (let's say, or D, or both if it's both lines of a pair). A then phones B, then, C, then D. You then have a boomerang bell. A sends 2-2-2 to B. B does not acknowledge, but instead sends 2-2-2 to C, who sends it to D who then acknowledges it back to C and pegs train on line. C then acknowledges it back to B who acknowledges it back to A.

It's all there in TS3, although I understand that the relevant section, (reg 3.6 part C off the top of the old noggin) has been heavily revised in the December 2021 Rule Book update, but I haven't received a hard copy yet.

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Engineering possessions on AB lines 15/11/2021 at 17:04 #142343
headshot119
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First of all just to clear up that a possession (AKA a T3) is different to a line blockage. The first is covered by rulebook module T3, the latter is covered by TS1 Reg 13.

In the present day, the bellcode 2-2-2 (Block line for protection purposes) is used when granting a line blockage, or a T3 through an Absolute Block section, this causes the signaller in advance to place the block indicator to TOL. When the work is completed, and the line blockage or T3 is given up, the bell code 1-2-2 (Line blockage completed) is used to allow the signaller in advance to place the block back to normal.

Blocking back inside the home signal (2-4) and obstruction removed (2-1-2) may also be needed where a T3 has worksite marker boards within the clearing point, or where a line blockage is affecting the safety of the line within the clearing point.

For T3s generally all the boxes involved will coordinate as to who will take the lead with the PICOP. For a line blockage the signaller who controls the primary protecting signal is responsible for the granting and cancelling of the line blockage. For example on Cheshire Lines if someone wanted to block both the up and down lines between Plumley West and Mobberley, the signaller at Plumley West would grant the up line blockage, and the signaller at Mobberley would grant the down.

"Passengers for New Lane, should be seated in the rear coach of the train " - Opinions are my own and not those of my employer
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Engineering possessions on AB lines 16/11/2021 at 09:09 #142347
kbarber
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That is really interesting. In my days when the dinosaurs ruled, there were no bell signals. The PICOP (previously known simply as PIC) would come to a clear understanding with the signalmen involved and the bobbies would advise each other by phone when the block was actually taken and given up. The block would be turned to TOL and back to Normal as part of that process, one of the few occasions you could legitimately operate the block without exchanging bell signals.

In those days, 2-2-2 was 'Line clear to clearing point only' if you were on the Western Region, and mostly used as a special (routing) Train Entering Section signal elsewhere. I can understand they have probably fallen completely out of use. But 1-2-2 was a class 7 and I think they still exist, so what's the code for one of them these days?

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Engineering possessions on AB lines 16/11/2021 at 10:39 #142348
TUT
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kbarber in post 142347 said:
In those days, 2-2-2 was 'Line clear to clearing point only' if you were on the Western Region, and mostly used as a special (routing) Train Entering Section signal elsewhere. I can understand they have probably fallen completely out of use.
Pretty sure the Southern still has routing train entering section signals. Routing bell codes generally are definitely in use elsewhere, for example in the Worcester area, very roughly speaking, for a train going left you add 3-4 to the standard is line clear and for a train going right you add 1-5. Hence, for a class 2 train going left towards Foregate Street and Henwick box, Norton Junction will send 3-1-3-4 to Shrub Hill.

kbarber in post 142347 said:
But 1-2-2 was a class 7 and I think they still exist, so what's the code for one of them these days?
4-1

Last edited: 16/11/2021 at 10:40 by TUT
Reason: None given

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Engineering possessions on AB lines 16/11/2021 at 13:37 #142354
Ron_J
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kbarber in post 142347 said:
That is really interesting. In my days when the dinosaurs ruled, there were no bell signals. The PICOP (previously known simply as PIC) would come to a clear understanding with the signalmen involved and the bobbies would advise each other by phone when the block was actually taken and given up. The block would be turned to TOL and back to Normal as part of that process, one of the few occasions you could legitimately operate the block without exchanging bell signals.
It was changed a few years ago because, as you say, the powers that be in Milton Keynes felt it was inconsistent with the rest of the regulations to move the commutator without sending a bell first (cf. the use of one beat when dropping the block for an adjacent line following the passage of an out of gauge load).

‘Is Line Clear’ for a Class 7 is 4-1.

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