Shortest section of single track

[Tomnick]

I wonder how you can get confused over that... They are both the same thing.

ComUtoR is correct - they are not the same thing.

Working a single line by Pilotman does what it says on the tin. You're using a Pilotman to maintain the integrity of a single line because the signalling system is unable to do so for some reason.

Single Line Working is working traffic in both directions over one line of a double line (or more) railway.

All the actual single lines in this country have rules that govern them, all that is required to give access to that line pictured is the clearance of the junction signal, while access to a real single line requires the issuing of a token, that token may take the form of a token from a Tyre's electric token instrument, a train staff or a radio telegram.

I do agree, but I'd point out that there are many single lines - TCB or Tokenless Block - where all that is required is the clearance of the junction signal, with no token involved. There are, of course, controls within the interlocking and/or separate instruments to indicate the state of the section.

 

[yorksrob]

In terms of proper sections of single track i.e. not junction turnouts, the four single track sections between Tonbridge and Bo-Peep junction must be comparatively short.

For those unaware, the single track sections were introduced through four tunnels before electrification in order to eliminate the need for special narrow bodied rolling stock. (The tunnels had been built as double track with two few layers of lining. The extra layers had to be built in, resulting in them being narrower than standard)

 

[Tomnick]

What about Criananlarich? See photo, one set of points for the split to either side of the platform and one for a main junction between the Oban and Fort William lines. Northbound trains split and then depart for separate destinations, no problem you can visually see when the points have been cleared. Southbound, however, with joining trains where is the single line token to? As an example, from RTT. 1Y44 from Fort William leaves Upper Tyndrum at 1319 and arrives at Crianlarich at 1327. meanwhile 1Y24 from Oban leaves Tyndrum Lower at 1320 while the Fort William train is in section, and arrives at Crianlarich at 1331. Both trains continuing at 1337 as 1Y44.
Now, do BOTH trains have a token to Crianlarich or is it to just before the points, making the bit between the two sets of points a separate single track?
Perhaps one of the more knowledgeable signallers could enlighten me.

It seems that is covered in the local instructions
View attachment 69291

For completeness, the local instructions in question are quoted below in all their glory. I'm not sure that they add much, to be honest. The fact that a separate token is issued for the last half-mile or so on each route approaching Crianlarich complicates things, but in practice I don't see that it's very much different to signals protecting the junction at the end of a conventionally signalled single line - the single line itself is physically defined by the points at each end, although there might be any number of signals (as well as the token or whatever other system is used to protect the integrity of the single line) to control the movement of trains along it. In this case, the token issued for the last bit into Crianlarich is more about protecting the conflicting moves across the junction rather than protecting the single line itself.

SC141 - CRAIGENDORAN JN TO FORT WILLIAM
CRIANLARICH TEP
Joining and splitting of trains - The following arrangements apply :-

Joining - The first train to enter the platform must be brought to a stand at the far end of the station and return the token.

The second train will be issued with a 'Loop Occupied' token at Fillan or Lower Crianlarich, as the case may be, and the driver reminded, when being given permission to proceed, that the loop line is occupied. In the event of a failure of all cab equipment in the second train, a special authority card may be used provided Clause (a) on the special authority card is endorsed 'Loop Occ'.

Splitting - Before uncoupling is carried out, the radio number of the rear train must be entered in the system.

After the first train has passed clear of the loop line, the rear train may draw forward to the combined stop board / points set indicator provided station duties have been completed, all is in order for the train to commence the movement and the conductor has sent the bell / buzzer code 6, to the driver. Before requesting a token to proceed, the driver must advise the signaller that he is at a stand at the stop board.

If only one radio is operational on the train, it may be split but the portion with the working radio must proceed to Oban. If all radios are non-operational but the radio / signalling system is still in working order in the Crianlarich area, the train must not be split but proceed to Fort William in accordance with Instruction 6, clause 6.2. of the instructions Single Lines Worked by Radio Electronic Token Block - Instructions to Traincrews, Persons carrying out Engineering Work and Others Concerned.

If splitting requires to take place during the period of a failure of the radio / signalling system affecting all trains in the Crianlarich area prior to the introduction of RETB Working by Pilotman, each portion may be allowed to proceed from Crianlarich in accordance with Instruction 6, clause 6.2. of the instructions Single Lines Worked by Radio Electronic Token Block - Instructions to Traincrews, Persons carrying out Engineering Work and Others Concerned. 'Loop Occupied' tokens - The Up direction 'Loop Occupied' tokens available for issue at Fillan and Lower Crianlarich must only be used for booked joining and splitting of Sprinter trains at Crianlarich and for providing assistance to a train which has failed in the Up loop at Crianlarich.

Junction and North end loop points - The hydraulic spring-controlled North end crossing loop points are train-operated in accordance with the standard arrangements for RETB crossing loops. The junction points are power operated clamp lock points, and are plunger operated for Down direction movements and track circuit operated for Up direction movements.

Two pairs of plungers are provided at the North end of the station at the bottom of the platform ramp, one pair in association with the Down loop 'Points Set' indicator, and one pair in association with the Up loop 'Points Set' indicator. These plungers must be operated only under the instructions of the signaller at Banavie signalling centre. Pressing the left-hand plunger of a pair of plungers sets the junction points for the Oban branch. Pressing the right-hand plunger of a pair of plungers sets the points for the main West Highland line for Upper Tyndrum. The illumination of the appropriate 'Points Set' indicator together with the correct route indication - 'B' for the branch or 'M' for the main line - after the operation of a plunger, prove that the junction points are correctly set and locked for the route chosen. Only the pair of plungers at the 'Points Set' indicator at which the train is standing can be used.

a) Down direction trains - When the driver of a Down direction train has been issued with a token and is ready to proceed, the signaller will authorise the driver to select the correct route at the same time as permission to proceed is given.

If either of these indications fail to illuminate when a plunger is operated, or if the indications illuminate but extinguish before the train can proceed past the 'Points Set' indicator, then the driver must communicate with the signaller and act in accordance with his instructions.
b) Up direction trains - If the driver of an Up direction train on the main or branch line finds that the 'Points Set' indicator on the approach to Crianlarich is displaying a single red flashing aspect or is not illuminated, he must immediately inform the signaller at Banavie signalling centre who will instruct him to unlock the lockfast box beside the indicator post and report the indications displayed inside. The driver must then act in accordance with the instructions of the signaller, and must not proceed past the indicator without the verbal permission of the signaller. Instruction 8 of the Single Lines Worked by Radio Electronic Token Block - Instructions to Traincrews, Persons carrying out Engineering Work and Others Concerned, is modified accordingly. When such verbal permission is given, the driver must not proceed until he has relocked the box and confirmed to the signaller that this has been done.

c) Failure of North end loop points - When the 'Points Set' indicator displays a single red flashing aspect or is not illuminated, the driver of an Up direction train is instructed by the signaller at Banavie signalling centre to manually operate the North end loop points, he must operate the points to the required position and clamp and scotch them in that position. An assurance must be given to the signaller at Banavie signalling centre when this has been done. The driver must not pass the 'Points Set' indicator unless the signaller at Banavie signalling centre has given permission to do so and the lockfast box at the 'Points Set' indicator has been relocked. When the train has passed clear of the points, the clamp and scotch must be removed, returned to the receptacle provided and an assurance to this effect given to the signaller at Banavie signalling centre when this has been done.

d) Override switch for junction points - The override switch for the junction points is located in the lockfast box adjacent to these points. This override switch normally lies in the centre position. Switching it to the left sets the points for the main line. Switching it to the right sets the points for the Oban branch. When operated to a position, the switch will remain in this position until it is again operated. This switch must only be operated under the instructions of the signaller at Banavie signalling centre.

If instructed by the signaller to operate this switch, the driver, or other person concerned, must carry out the following procedure :-
1. if the points are already in the correct position for the route required, the driver, or person concerned, must operate the switch for the other route, check that the points have moved to the other route, and then operate the switch to the route required and check that the points have moved to the route required.
2. if the points are not already in the correct position for the route required, the driver, or person concerned, must operate the switch for the route required and check that the points have moved to this position. He must then operate the switch for the other route, check that the points have moved to this position, and then operate the switch for the required route again, and check that the points are in the correct position for the route required.

If the override switch fails to move the points to the required position, the driver, or person concerned must report this to the signaller, who will send for the person appointed to manually operate the junction points. The driver must not pass the 'Points Set' indicator until he receives the verbal permission of the signaller.

If the points have been operated to the required position, the driver must confirm this to the signaller. The driver of a Down direction train must operate the appropriate plunger again, when so instructed by the signaller. If the correct route indication can still not be obtained, in certain failure conditions, the driver must then be instructed to proceed to the lockfast box at either the up branch or the up main Points Set Indicator (which ever is relevant to his intended direction of travel) and report the indications on display therein. If both Junction Points and Loop Points indications are confirmed by the driver to be illuminated then the relevant down train may be authorised to proceed over the junction points. The driver must also be instructed to restore the junction points to the main position and the override switch to the centre position and confirm this has been done before continuing. The driver must also confirm that he has also relocked the relevant lockfast box at the Up Main or Up Branch Points Set Indicator.

The driver of an Up direction train must report to the signaller whether the 'Points Set' indicator is now illuminated, and must then act on the instructions of the signaller. He must not pass the 'Points Set' indicator without the verbal permission of the signaller. When such permission is given, before proceeding, the driver must relock the lockfast box beside the indicator post and confirm to the signaller that this has been done.

When the driver of an Up or Down direction train has proceeded over the junction points after the operation of the override switch, and the train is clear of both the loop points and the junction points, he must return the override switch to the centre position, relock the box and confirm to the signaller when this has been done.
a) Engineers' machines - An engineer's machine which cannot be relied upon to actuate track circuits must not proceed over the junction points to / from Tyndrum Lower until the override switch has been operated under the instructions of the signaller at Banavie signalling centre.

Drivers of Down direction machines will be instructed to operate the override switch before operating the appropriate plunger.

Drivers of Up direction machines must stop at the 'Points Set' indicator on the approach to Crianlarich, even if it is illuminated, and act under the instructions of the signaller. The override switch must be operated in accordance with the previous instructions under the heading Override switch for junction points.

Engineering Possessions - If an engineering possession is required between the two single sided Station Limits boards between Crianlarich and Tyndrum Lower, the engineer must be in possession of both the Crianlarich to Tyndrum Lower 'Engineering' token and also the Crianlarich 'Shunt' token. Before the signaller issues the 'Shunt' token, the engineer must set the junction points for the branch under the instructions of the signaller, and in accordance with the instructions under the heading Override switch for junction points. When the 'Shunt' token is returned, the engineer must confirm to the signaller that the override switch has been returned to the centre position, and the box relocked.

RETB Working by Pilotman - If it is necessary to divide a Down direction passenger train or combine Up direction passenger trains at Crianlarich, two Pilotmen must be appointed to the following sections simultaneously -
Pilotman A - Ardlui (or south thereof) and Upper Tyndrum.
Pilotman B - Crianlarich Lower GF and Dalmally (or west thereof).

Down trains to be divided - Down trains must be accompanied by Pilotman A between Ardlui (or south thereof) and Crianlarich. After the train has been divided, providing Pilotman B is present and permission for the train to occupy the Crianlarich / Tyndrum Lower section has been obtained, Pilotman A may authorise the train to proceed. After Pilotman A has checked visually that the first portion has passed the Down branch 'loop clear' marker at Crianlarich, he may then obtain permission for the second portion to proceed towards Upper Tyndrum and then authorise it to proceed.

Up trains to be combined at Crianlarich - Up trains from Upper Tyndrum must be accompanied by Pilotman A between Upper Tyndrum and Crianlarich. On arrival at Crianlarich, Pilotman A must proceed on foot or by road to Crianlarich Lower GF. Up trains from Oban must be accompanied by Pilotman B as far as Crianlarich Lower GF where he must detrain. Pilotman A must then, with the authority of the signaller, conduct the train from Crianlarich Lower GF on to the rear of the front portion at Crianlarich. After both portions have been coupled together, Pilotman A must then obtain permission from the signaller and then authorise the combined trains to proceed to Ardlui (or south thereof).

Dividing and combining trains - In each case, Pilotman A must issue a separate Pilotman's Written Authority to Proceed form to (a) allow the train to proceed as far as Crianlarich and (b) allow the train to proceed beyond Crianlarich. The signaller must record the time at which each train enters or leaves the section as shown in clause 4.1 of the RETB Working by Pilotman instructions for each written authority.
Dated: 30/01/16

 

[ElectroSoldier]

Er... They most certainly are not.

And yet to some of these people they are!!!

 

[sw1ller]

And yet to some of these people they are!!!

Are “some of these people” you? Because it’s you that seems confused here.

 

[6026KingJohn]

For completeness, the local instructions in question are quoted below in all their glory. I'm not sure that they add much, to be honest. The fact that a separate token is issued for the last half-mile or so on each route approaching Crianlarich complicates things, but in practice I don't see that it's very much different to signals protecting the junction at the end of a conventionally signalled single line - the single line itself is physically defined by the points at each end, although there might be any number of signals (as well as the token or whatever other system is used to protect the integrity of the single line) to control the movement of trains along it. In this case, the token issued for the last bit into Crianlarich is more about protecting the conflicting moves across the junction rather than protecting the single line itself.

Thank you very much, It does help. It was, as you say, the issuing of a second token which complicated matters.

 

[fairysdad]

Would the short section of single track at the junction between the GWR and SWR lines at Dorchester count?

 

[james60059]

Gibbet Hill Junction to Kenilworth is quite short, 1m75ch.

 

[6026KingJohn]

Gibbet Hill Junction to Kenilworth is quite short, 1m75ch.

Stourbridge Junction to Stourbridge Town is 0m 62ch

 

[66Yorks]

Why is that even a thing? Was the bridge weak on one side?

It certainly isn't weak now as the bridge was completely renewed a couple of years ago. Like someone who previously stated, probably to save a bit of money.

 

[MotCO]

Wasn't there a bit of single line between London Bridge going on to the rising track towards Blackfriars. The rising track was mostly double track, but there was a small section of single track near the junction probably due to space constraints. Or am I mis-remembering? Is it still there?

 

[ComUtoR]

Or am I mis-remembering? Is it still there?

It was there, now its been doubled all the way.

 

[Belperpete]

Wasn't there a bit of single line between London Bridge going on to the rising track towards Blackfriars. The rising track was mostly double track, but there was a small section of single track near the junction probably due to space constraints. Or am I mis-remembering? Is it still there?

If people are going to claim every single piece of bi-directional track between two sets of adjacent points is "single-line", then this thread is surely going to extend to thousands of examples. The junction you refer to was surely just a variation on a single-lead junction, of which there are (or were) numerous examples. As others have already noted, there is a difference between a single track and "single line".

 

[Llama]

The Up & Down Hellifield near Blackburn is most certainly a single line in the proper sense of the term (TCB method of working, modified working authorised) - it's 25 chains from the junction with the East Lancs lines to where it becomes double line again.

 

[ElectroSoldier]

The Up & Down Hellifield near Blackburn is most certainly a single line in the proper sense of the term (TCB method of working, modified working authorised) - it's 25 chains from the junction with the East Lancs lines to where it becomes double line again.

Thats an interesting one. I dont know that personally.
If its Track Circuit Block what do they use as a token to access the single line?

 

[Llama]

There's no token on TCB single lines. All done by slot & track circuits. There are quite a few TCB single lines around the north west.

 

[ElectroSoldier]

So clearing the section signal counts as the authority to occupy the single line then!

 

[Belperpete]

The Up & Down Hellifield near Blackburn is most certainly a single line in the proper sense of the term (TCB method of working, modified working authorised) - it's 25 chains from the junction with the East Lancs lines to where it becomes double line again.

The chord at Lichfield (between the WCML and the Aston-Lichfield City-Derby line) is likewise a proper TCB single-line controlled by slots, and also cannot be very long.

 

[Tomnick]

The Up & Down Hellifield near Blackburn is most certainly a single line in the proper sense of the term (TCB method of working, modified working authorised) - it's 25 chains from the junction with the East Lancs lines to where it becomes double line again.

It’s an interesting one as there’s no signals on the single line itself, so the slots in each direction are as much about protecting the junction at the far end than about the integrity of the single line!

(Incidentally, it’s common on TCB single lines for one box to be able to pull off onto the single line whenever they wish - as long as it’s clear! - with the other end needing a slot to clear their signal)

Thats an interesting one. I dont know that personally.
If its Track Circuit Block what do they use as a token to access the single line?

The vast majority of single lines are signalled like this nowadays, with no tokens needed or indeed provided. The interlocking looks after it all, and in many cases it’s all under the control of one box.

 

[Belperpete]

The vast majority of single lines are signalled like this nowadays, with no tokens needed or indeed provided. The interlocking looks after it all, and in many cases it’s all under the control of one box.

But if its all under the control of the same box, is it "single line"?

 

[ElectroSoldier]

Yes.
A good case in point is Buxton up to Hindlow.
There is only 1 signal box on end and a set of points to a siding the other.
The key token is issued by the box and the trainman locks himself into the sidings at the other, when he wants to come out he has to ask the signaller at Buxton to give the now locked in key token.

Tokens come in many forms, they are not always a key, some kind of token is always issued even if you dont recognise it as a token.

 

[najaB]

But if its all under the control of the same box, is it "single line"?

Well, it's a signalled stretch of mainline railway connecting A to B used by trains going in either direction without a parallel track such that a train from A to B has to wait for a train from B to A to clear the section. It sounds like a single line to me.

 

[Belperpete]

Yes.
A good case in point is Buxton up to Hindlow.
There is only 1 signal box on end and a set of points to a siding the other.
The key token is issued by the box and the trainman locks himself into the sidings at the other, when he wants to come out he has to ask the signaller at Buxton to give the now locked in key token.
Tokens come in many forms, they are not always a key, some kind of token is always issued even if you dont recognise it as a token.

Single lines can also be worked by "Tokenless Block" (which by definition doesn't have a token) - quite popular at one time in Scotland, but also used in a few cases on the Southern (the single line near Appledore springs to mind). Or by Track-Circuit Block, which as previously mentioned usually incorporates some form of slot, release or acceptance control (but no token of any kind) between the two signalboxes.

Well, it's a signalled stretch of mainline railway connecting A to B used by trains going in either direction without a parallel track such that a train from A to B has to wait for a train from B to A to clear the section. It sounds like a single line to me.

Nop, that just sounds like a bit of single-track to me, as opposed to "single line" which usually means there are two boxes involved.

You can get two parallel single-lines. The case that comes to mind was Waddon to Beddington (pre-Tramlink) where there were two parallel tracks (one passenger and one freight), both worked as single lines with each having their own staff instruments between the two boxes.

Things become a bit blurred with NSTR (No Signaslman Token Remote) and NSKT (No Signalman Key Token) and such-like, where one or both ends of the single-line section has no signalbox (often because it was rationalised away). I think Buxton to Hindlow comes into this category. And the Central Wales line, where the signalboxes at both ends of the sections were rationalised away.

The difference between a bit of bi-directionally-signalled single-track and a single-line, is the method of working, particularly when the signalling fails. On a single-line, the signaller can't just authorise a train to pass the section signal at red if the signalling fails - usually some kind of special working (such as pilotman working) is necessary.

In theory, you could get two sets of points back-back with no distance at all between the two, which by the logic employed by some would mean you would have a single-line of zero length. (As has previously been pointed out by others, PW set a practical limit to how close you can get two points back-back, particularly if S&T want a set of insulated joints between the two) If you want the divergencies any closer, you end up with a double-slip. If people are going to claim every set of back-back points as contenders for the shortest bit of single-line, then I will start thinking of examples of double-slips, which by reductio ad absurdum must therefore be sections of single-line with negative length!

 

[ElectroSoldier]

Single lines can also be worked by "Tokenless Block" (which by definition doesn't have a token) - quite popular at one time in Scotland, but also used in a few cases on the Southern (the single line near Appledore springs to mind). Or by Track-Circuit Block, which as previously mentioned usually incorporates some form of slot, release or acceptance control (but no token of any kind) between the two signalboxes.

Thats true however the clearing of the section signal is the authority to the driver to ocupy the single line.
A token is authority to enter and occupy a single line... It does not always come in the form of a physical key.
I know a few lines up in the North West that use tokenless block. Moldsworth to Mickletrafford springs to mind.
The West Highland line uses Radio telegrams as their tokens...

Nop, that just sounds like a bit of single-track to me, as opposed to "single line" which usually means there are two boxes involved.

You can get two parallel single-lines. The case that comes to mind was Waddon to Beddington (pre-Tramlink) where there were two parallel tracks (one passenger and one freight), both worked as single lines with each having their own staff instruments between the two boxes.

Things become a bit blurred with NSTR (No Signaslman Token Remote) and NSKT (No Signalman Key Token) and such-like, where one or both ends of the single-line section has no signalbox (often because it was rationalised away). I think Buxton to Hindlow comes into this category. And the Central Wales line, where the signalboxes at both ends of the sections were rationalised away.

The difference between a bit of bi-directionally-signalled single-track and a single-line, is the method of working, particularly when the signalling fails. On a single-line, the signaller can't just authorise a train to pass the section signal at red if the signalling fails - usually some kind of special working (such as pilotman working) is necessary.

In theory, you could get two sets of points back-back with no distance at all between the two, which by the logic employed by some would mean you would have a single-line of zero length. (As has previously been pointed out by others, PW set a practical limit to how close you can get two points back-back, particularly if S&T want a set of insulated joints between the two) If you want the divergencies any closer, you end up with a double-slip. If people are going to claim every set of back-back points as contenders for the shortest bit of single-line, then I will start thinking of examples of double-slips, which by reductio ad absurdum must therefore be sections of single-line with negative length!

A "single line" does not require a signal box at both ends, it doesnt even require a signal box at either end of the single line, there must however be a method of controlling access to the single line. And this is where peoples idea of what a token is falls over.

Buxton uses a Tyers electric token machine to control access to single line down to Great Rocks and another up to Hindlow. At Great Rocks there is a signal box to issue the token, when released at Great rocks by agreement with Buxton, which is to say the ones asks the other if its ok to send a train down, releasing the token is his agreement and the release of the token locks the line for only the one movement from Great rocks to Buxton, interlocking prevents Buxton from clearing the section signal into the single line.
To Hindlow there is a very similar Tyers electric token machine, the signaller bells out a token when he wants one, the token machine will release a token when there is no other token already out on the line. He gives that key token to the driver of the train who takes it with him and litterly uses it to unlock the switch into one of the sets of sidings up there. Once in the sidings, having checked his train has arrived complete he will change the switch away from the siding and lock the points belling out as he does so to return the key token into the machine. Its at that point the token machine at Buxton is able to release another token to access the single line in either direction. To come back down the hill the driver will push the plunger on the token machine, the signaller at Buxton will answer and if there is no key token already out the machine will release a key that can be used to unlock the switch that is keeping him in the sidings and go back down to Buxton.

A no signalman key token system uses a similar system to the traditional Tyers electric token machines operated by a signalman, however the machines that release the token are interlocked to each other, the machine you want to take a token from will know if a token has either been removed at the other end or has been removed from it and not replaced in the machine the other end, thus a single lines safety is assured by interlocking the machines together, those keys are also actual keys that unlock points that are used to access the single line from the passing places provided along the line. or the passing loops can use automatic self detecting facing points that will lock away from the passing loop in one direction and unlock when travelling in the other thus no signaller is required to move the points over.

Even No-Signalman Token on Single Lines with Remote Crossing Loops have a signalman, he just isnt at the end of or even anywhere near the single line.

 

[ComUtoR]

It’s an interesting one as there’s no signals on the single line itself,

If you had a long section of 'single line' that had signals. Could you, stick multiple trains down in the same direction or would you think of that as being a 'reversible/Bi-Di' line ?

 

[Belperpete]

If you had a long section of 'single line' that had signals. Could you, stick multiple trains down in the same direction or would you think of that as being a 'reversible/Bi-Di' line ?

I seem to recall seeing reference to permissive token instruments. You can certainly get multiple-section TCB-worked single-lines. The signalman can give the slot/release/acceptance, but is prevented from normalising it until the whole single-line is clear.

 

[Tomnick]

If you had a long section of 'single line' that had signals. Could you, stick multiple trains down in the same direction or would you think of that as being a 'reversible/Bi-Di' line ?

I used to have a single line with an intermediate signal at one of my boxes and it was absolutely fine to stick a second train down there (as long as the other chap gave me the slot!). It was definitely a single line as opposed to a bi-directional line, which was a very important distinction when it comes to needing a Pilotman (you can “nominate a direction” on a bi-di line, e.g. a reversibly signalled line that’s normally worked in the Up direction only anyway, thus not needing a Pilotman).

 

[Belperpete]

Thats true however the clearing of the section signal is the authority to the driver to ocupy the single line.
A token is authority to enter and occupy a single line... It does not always come in the form of a physical key.
I know a few lines up in the North West that use tokenless block. Moldsworth to Mickletrafford springs to mind.
The West Highland line uses Radio telegrams as their tokens...
A "single line" does not require a signal box at both ends, it doesnt even require a signal box at either end of the single line, there must however be a method of controlling access to the single line. And this is where peoples idea of what a token is falls over.

I am no clearer as to what you are trying to say. Agreed, tokens don't always come in physical form: with RETB there is no physical token, it is (as the name suggests) an electronic token. But with Tokenless Block and TCB single-line block, there is no token at all: physical, electronic or of any other kind. In such cases, the section signal is the sole authority to both enter and occupy the single-line.

 

[najaB]

Nop, that just sounds like a bit of single-track to me, as opposed to "single line" which usually means there are two boxes involved.

In the old days, I'd agree. But given the geographic scope that can be controlled from a PSB, never mind from a ROC that distinction doesn't really make sense any more.

 

[ComUtoR]

It was definitely a single line as opposed to a bi-directional line, which was a very important distinction when it comes to needing a Pilotman.

I checked through my rulebook and there is no definition of a 'single line' I know in my rules notes from many a moon ago that I have drawings of each but no reference.

The railway drives me mad with definitions. Reversible/Bi-Di/Single line/SIMBID Arghhhhhhh !!!

Good to know that you could send multiple trains onto a single line. I have a few short sections of single line but I kinda remembered one where you can get a train up behind you and wasn't sure if that would be considered a 'reversible' I think it was token, way back in the day, but the line got upgraded to TCB.