Signalling for modellers who don't know much about signalling

[Pacific231G]

.  Don't get me started about train formations or locos without continuous brakes on passenger trains, or privately owned factory locos running around loose all over BR...

 

Question on that last point. A private siding- which could be an extensive works system with its own signalling- would have a trap point or an arrangement of points to protect BR's running lines but, when the sidings were open to the running lines for a mainline loco to shunt wagons in and out, what rules would then affect a works loco working in the private area?  Would there ever be direct access to the works system from the mainline or would there always be an intermediate exchange siding. if so what penetration of BR (GWR, LNER etc.) by works locos would be permitted and vice versa?   

 

Edited October 25, 2017 by Pacific231G

[St. Simon]

Another common one is trains approaching a speed restricted turnout into a loop or junction for which the signal has been cleared; the more correct procedure would be for the signalman to bring the train to or almost to a stand before clearing the appropriate signal similarly to the example above.  In modern signalling, this sort of situation is 'approach lit' by the proximity and speed of the train; if it is approaching too quickly over more than one sensor, the signal will not clear and the driver has to phone the signaller to ask for the road; the same principle is employed.

 

Not quite...

 

The actual term is 'Approach Released' or 'Approach Controlled', I've heard both used interchangeably, this is where the Junction Protecting Signal is either held at Red (MAR - Main Aspect Approached Released from Red) or at Single Yellow (MAY - Main Aspect Approach Released from Yellow) until either the train is proved to be at a appropriate speed or it has reached the point at which the route indication is readable, it will then step up to the next appropriate aspect dependent on what aspect the next signal is showing. The driver does not have to phone the signaller if the signal doesn't clear until he is at a stand.

 

The above is done through track circuits or axle counters in the following manner for the two different release scenarios

 

• Proving the train is at a certain speed - The occupation of the Berth Track Circuit is timed to prove the train has slowed sufficiently
• Proving the train is at a certain point - One of the Track circuits between the signal and the release point has to be occupied, and if the release point is in the middle of track circuit, the track circuit occupation is timed so the train reaches the release point before the signal steps up.

Of course, MAY can be split into MAY-FA (MAY with Flashing Aspects, the most common), MAY-SD (MAY with Splitting Distant) or MAY-YY (MAY with consecutive yellows, very rare and not allowed new anymore).

 

The term 'Approach Lit' refers to where a signal displays no aspect until the approach of a train, the aspect being activated by track circuit or axle counter operation far enough back so a train can be stopped by another signal if the Approach lit signal hasn't been proved illuminated. The use was very short lived, but is now making a come back with the use of battery or solar power packs for signals (particularly Distant Signals).

 

The system that enforces speed on the approach to a signal is TPWS, Train Protection and Warning System, this uses two radio frequencies generated in 'arming' and 'trigger loops' on approach (and immediately adjacent) to some stop signals, which are activated by the signal being at danger. If a train passes over these two loops and the train has detected that it has passed over the two loops within 1 seconds of each other, the brakes are applied.

 

Hope this helps!

 

Simon

[big jim]

A very well written reply simon but you may as well just written "approach release signals don't exist"

 

(Ok we know they do but as a driver we are told from day one that they don't exist to avoid the temptation of just powering up to a signal thinking it will pull off and it doesn't)

[The Johnster]

Question on that last point. A private siding- which could be an extensive works system with its own signalling- would have a trap point or an arrangement of points to protect BR's running lines but, when the sidings were open to the running lines for a mainline loco to shunt wagons in and out, what rules would then affect a works loco working in the private area?  Would there ever be direct access to the works system from the mainline or would there always be an intermediate exchange siding. if so what penetration of BR (GWR, LNER etc.) by works locos would be permitted and vice versa?   

 

 

 

You won't go far wrong if you adopt the general principle that 'works' locos are not permitted to pass the signal inside the works system protecting the trap point.  The point to which 'big railway' engines are allowed to run on the works system is either marked by a stop board stating that 'GW (or whoever's) locomotives must not pass this board' or similar, or as instructed in the Sectional Appendix (to the Rules and Regulations, and local instructions for a specific area) for that particular system.  Axle loading, clearance, condition of track, and curvature would be amongst the factors preventing main line locos operation over parts of works systems.

 

There are exceptions, especially for NCB locos in the North East of England, where the NCB ran vacuum fitted passenger workmen's services as well as mineral traffic over the big railway's tracks; there may be other local arrangements of which I am not aware.  In South Wales, it was not unusual to see NCB locos hauled dead in freight trains, marshalled directly behind the loco or the fitted head if there was one, to have wheel profiling work done at Canton shed or to be transferred between pits, but not in steam and not hauling trains.  

 

Works locos in this sense include those on large systems at steelworks, docks, NCB and such which might operate alongside big railway locos for considerable distances and over large exchange yards or sidings; the area between Margam yard and Port Talbot steelworks being a notable example.

 

But, unless you are specifically modelling such a location or imaginary location, keep your works loco in the works.

 

As for working in the works yard while there is open access to the big railway, local rules would apply.  Shunting movements in yards and sidings are not controlled by fixed signals, but by handsignals from qualified and authorised staff, at low speed (15mph maximum, whatever you've seen in your local yard when everybody wants an early finish on a Saturday morning when there's a match on), and safety is reliant on co-operation between men on the ground and drivers keeping a sharp all round look out for other conflicting movements.  This is applicable in big railway yards where more than one locomotive may be operating as well as in works sidings.

 

Hope this helps!

[The Johnster]

Not quite...

 

The actual term is 'Approach Released' or 'Approach Controlled', I've heard both used interchangeably, this is where the Junction Protecting Signal is either held at Red (MAR - Main Aspect Approached Released from Red) or at Single Yellow (MAY - Main Aspect Approach Released from Yellow) until either the train is proved to be at a appropriate speed or it has reached the point at which the route indication is readable, it will then step up to the next appropriate aspect dependent on what aspect the next signal is showing. The driver does not have to phone the signaller if the signal doesn't clear until he is at a stand.

 

The above is done through track circuits or axle counters in the following manner for the two different release scenarios

 

• Proving the train is at a certain speed - The occupation of the Berth Track Circuit is timed to prove the train has slowed sufficiently
• Proving the train is at a certain point - One of the Track circuits between the signal and the release point has to be occupied, and if the release point is in the middle of track circuit, the track circuit occupation is timed so the train reaches the release point before the signal steps up.

Of course, MAY can be split into MAY-FA (MAY with Flashing Aspects, the most common), MAY-SD (MAY with Splitting Distant) or MAY-YY (MAY with consecutive yellows, very rare and not allowed new anymore).

 

The term 'Approach Lit' refers to where a signal displays no aspect until the approach of a train, the aspect being activated by track circuit or axle counter operation far enough back so a train can be stopped by another signal if the Approach lit signal hasn't been proved illuminated. The use was very short lived, but is now making a come back with the use of battery or solar power packs for signals (particularly Distant Signals).

 

The system that enforces speed on the approach to a signal is TPWS, Train Protection and Warning System, this uses two radio frequencies generated in 'arming' and 'trigger loops' on approach (and immediately adjacent) to some stop signals, which are activated by the signal being at danger. If a train passes over these two loops and the train has detected that it has passed over the two loops within 1 seconds of each other, the brakes are applied.

 

Hope this helps!

 

Simon

 

Thank you for the elucidation, Simon.  We used the incorrect term 'approach lit' at Canton in the 70s, and of course were not supposed to be aware that such signals existed for the reason you have pointed out.  I am not well informed in any more than the most general sense about systems adopted since the 70s...

[St. Simon]

A very well written reply simon but you may as well just written "approach release signals don't exist"

 

(Ok we know they do but as a driver we are told from day one that they don't exist to avoid the temptation of just powering up to a signal thinking it will pull off and it doesn't)

 

You're quite right, they do become a notable SPAD trap, and of course, we don't like them as they slow everything down!

 

Simon

[St. Simon]

Thank you for the elucidation, Simon.  We used the incorrect term 'approach lit' at Canton in the 70s, and of course were not supposed to be aware that such signals existed for the reason you have pointed out.  I am not well informed in any more than the most general sense about systems adopted since the 70s...

 

It's alright, I can see the reasoning behind using Approach Lit instead of Approach release, and nowadays good old phrases are being phased out. So now, there is no such thing as an 'Automatic' or 'Controlled' signal, they are now referred to in standards as 'Non-Route Setting' and 'Route Setting' Signals respectively, the term 'SPAD' is slowly being placed with 'Passing a Signal at Danger without Authority', 'Semi-Automatic' Signal has dispensed with long ago, it is now a Route Setting (previous Controlled) signal with an Automatic Working Facility.

 

There are some more recent terms that have been introduced to describe new types of signal, such as a 'Non-Approachable Red', which is basically a Distant signal capable of showing a Red aspect when no route is set over it.

 

Simon

[Junctionmad]

 

 

Another common one is trains approaching a speed restricted turnout into a loop or junction for which the signal has been cleared; the more correct procedure would be for the signalman to bring the train to or almost to a stand before clearing the appropriate signal similarly to the example above.  In modern signalling, this sort of situation is 'approach lit' by the proximity and speed of the train; if it is approaching too quickly over more than one sensor, the signal will not clear and the driver has to phone the signaller to ask for the road; the same principle is employed.

hmm, certainly in semaphores this would only be the case where rule 39(a) applied i.e. the the starter or loop exit signal was " on", if the route was clear the train would not be " checked " by the junction signal, Semaphores had no role in determining speed , only route guidance 

[The Johnster]

Indeed, but signalmen were instructed to bring trains 'to or almost to a stand' before clearing signals into loops or over speed restricted junctions and this was the usual practice.  Where a junction was 'high speed', i.e. the diverging line speed was 40mph or more and splitting distants were provided, of course the junction signal would be cleared for through running in the normal way.

[Junctionmad]

 

 

 signalmen were instructed to bring trains 'to or almost to a stand' before clearing signals into loops or over speed restricted junctions and this was the usual practice.

was it a common case? I wasn't aware it was , its certainly not in the rules 

Edited October 26, 2017 by Junctionmad

[Ray H]

One thing I've never fully understood and was (and may still be) witnessed on (at least) the southern end of the WCML was a junction home signal held at danger until the approaching train's speed had been "proven" to have dropped sufficiently. The junction signal was then cleared for the low speed divergent route with the next signal (in advance) on that divergent route inevitably green.

 

I always wondered why the junction signal wasn't cleared to single yellow and the next signal (on the divergent route) held at red at least until the front of the train (or more) had completed the crossing movement.

 

Another strange occurrence was where the junction home was sufficiently in the  rear of the turnout that a diverging train was often required to accelerate again before reaching the junction to negotiate the junction at (or about) the permitted maximum speed. That scenario was not unheard of (pre-TPWS?) on terminal platform roads where the train had to accelerate once on the platform track to actually reach the stops without undue delay. This was certainly prevalent on LUL at one stage as well.

[Pacific231G]

You won't go far wrong if you adopt the general principle that 'works' locos are not permitted to pass the signal inside the works system protecting the trap point.  The point to which 'big railway' engines are allowed to run on the works system is either marked by a stop board stating that 'GW (or whoever's) locomotives must not pass this board' or similar, or as instructed in the Sectional Appendix (to the Rules and Regulations, and local instructions for a specific area) for that particular system.  Axle loading, clearance, condition of track, and curvature would be amongst the factors preventing main line locos operation over parts of works systems.

 

There are exceptions, especially for NCB locos in the North East of England, where the NCB ran vacuum fitted passenger workmen's services as well as mineral traffic over the big railway's tracks; there may be other local arrangements of which I am not aware.  In South Wales, it was not unusual to see NCB locos hauled dead in freight trains, marshalled directly behind the loco or the fitted head if there was one, to have wheel profiling work done at Canton shed or to be transferred between pits, but not in steam and not hauling trains.  

 

Works locos in this sense include those on large systems at steelworks, docks, NCB and such which might operate alongside big railway locos for considerable distances and over large exchange yards or sidings; the area between Margam yard and Port Talbot steelworks being a notable example.

 

But, unless you are specifically modelling such a location or imaginary location, keep your works loco in the works.

 

As for working in the works yard while there is open access to the big railway, local rules would apply.  Shunting movements in yards and sidings are not controlled by fixed signals, but by handsignals from qualified and authorised staff, at low speed (15mph maximum, whatever you've seen in your local yard when everybody wants an early finish on a Saturday morning when there's a match on), and safety is reliant on co-operation between men on the ground and drivers keeping a sharp all round look out for other conflicting movements.  This is applicable in big railway yards where more than one locomotive may be operating as well as in works sidings.

 

Hope this helps!

It does help, thanks.

I've been wondering how this compared with practice elsewhere. I've come across examples in France of industrial lines and light railways that crossed main lines, either to reach exchange sidings or because there were installations on both sides, controlled by standard stop signals operated by the main line's frame or box.

 

There were crossings of main lines by private railways in Britain, the one that comes to mind was the crossing of the GW main line at Laira Junction by the 4ft 6in gauge Lee Moor Tramway. That was a gated crossing with the GW lines protected by signals just like a normal road level crossing but I wondered whether signal controlled crossings by private or light railways were ever permitted in Britain.

   

I know that the Port of London Authority Railway was signalled on the part of its Royal Albert Dock system between Custom House and Gallions which operated a regular passenger service but that was a statutory undertaking so just like any other public railway so far as regulations were concerned even though built on private land.

 

I did see the NCB's South Shields, Marsden & Whitburn Colliery Railway, or what was left of it,  operating around South Shields with electric locos when I was at college there in 1969 but that was sixteen years after the last passenger trains ran on it. As a passenger line it certainly had been fully signalled but I can't remember whether it still was.  . I think that crossed under the main line to South Shields Station to reach the NCB wharves on the Tyne so the question of signalling a main line crossing didn't arise.

 

Whilst there was no signalling within yards and sidings some private and industrial railways did have quite long "main line" runs so would those have been signalled even when they didn't carry passengers?

[St. Simon]

One thing I've never fully understood and was (and may still be) witnessed on (at least) the southern end of the WCML was a junction home signal held at danger until the approaching train's speed had been "proven" to have dropped sufficiently. The junction signal was then cleared for the low speed divergent route with the next signal (in advance) on that divergent route inevitably green.

 

I always wondered why the junction signal wasn't cleared to single yellow and the next signal (on the divergent route) held at red at least until the front of the train (or more) had completed the crossing movement.

 

Holding the Junction Protecting Signal at Danger is used so that where a divergent route has a lower speed by more than 10mph (or is outside of the speed 'bands' for MAY) than the straight on route, the train can be proven to be at the speed of the divergent route before passing the protecting signal to ensure it does not take the route at excessive speed. By holding the signal at red, the driver is forced to slow his train through the cautionary aspect sequence in rear.

 

It is used at the vast majority of divergent routes around the country

 

Simon

[RailWest]

>>>>There were crossings of main lines by private railways in Britain, the one that comes to mind was the crossing of the GW main line at Laira Junction by the 4ft 6in gauge Lee Moor Tramway...

 

Strictly speaking, it was the GWR crossing the LMT as the latter existed first - and I believe their horse-drawn 'trains' (theoretically) had priority :-)  There was another crossing of the LMT further along near Mount Gould Jcn, as well as one some way down the Tavistock Branch.

 

The S&DJR line to Glastonbury was crossed by the narrow-gauge line of the 'Eclipse' Peat works without any signalling - and became the scene of an accident one foggy morning.....

[St Enodoc]

You're quite right, they do become a notable SPAD trap, and of course, we don't like them as they slow everything down!

 

Simon

I thought that was the whole point...

[St. Simon]

I thought that was the whole point...

Yes, yes it is, but I'd rather have P-Way install nice long points so I don't have to use approach control, and speed up the whole layout.

 

Simon

[meil]

>>>>There were crossings of main lines by private railways in Britain, the one that comes to mind was the crossing of the GW main line at Laira Junction by the 4ft 6in gauge Lee Moor Tramway...

 

Strictly speaking, it was the GWR crossing the LMT as the latter existed first - and I believe their horse-drawn 'trains' (theoretically) had priority :-)  There was another crossing of the LMT further along near Mount Gould Jcn, as well as one some way down the Tavistock Branch.

 

The S&DJR line to Glastonbury was crossed by the narrow-gauge line of the 'Eclipse' Peat works without any signalling - and became the scene of an accident one foggy morning.....

There still is - the WHR crosses the "big" railway.

[TheSignalEngineer]

Indeed, but signalmen were instructed to bring trains 'to or almost to a stand' before clearing signals into loops or over speed restricted junctions and this was the usual practice.  Where a junction was 'high speed', i.e. the diverging line speed was 40mph or more and splitting distants were provided, of course the junction signal would be cleared for through running in the normal way.

 

was it a common case? I wasn't aware it was , its certainly not in the rules 

In the 1950 Rule Book for Absolute Block Working it was covered by Rule 39A. If you hadn't got a Line Clear so couldn't clear the Starting Signal then the Home Signal was maintained at danger until the train was at or nearly at a stand. If a berth track circuit was provided this would extend  200 yards on the approach side of the Home signal and would have to be occupied by the train before the Home signal could be cleared unless a Line Clear had been given by the next box in advance. If there were more Stop signals between the Home and Starting signals the signalman would clear each in turn as the train got to it. 

The Driver's understanding of this action was that Line Clear had not yet been received and he was being allowed to proceed at low speed subject to being able to stop at the next signal.

[beast66606]

In the 1950 Rule Book for Absolute Block Working it was covered by Rule 39A. If you hadn't got a Line Clear so couldn't clear the Starting Signal then the Home Signal was maintained at danger until the train was at or nearly at a stand. If a berth track circuit was provided this would extend  200 yards on the approach side of the Home signal and would have to be occupied by the train before the Home signal could be cleared unless a Line Clear had been given by the next box in advance. If there were more Stop signals between the Home and Starting signals the signalman would clear each in turn as the train got to it. 

The Driver's understanding of this action was that Line Clear had not yet been received and he was being allowed to proceed at low speed subject to being able to stop at the next signal.

 

On the Birkenhead lines a slow clearing meant "drop to the next one driver" - a signal whipped off would mean "I've got your road and I'm pulling them all off so you can open up".

 

I remember being on the Wirral 100 railtour in 1977, wanting a clear run - a blast -  from Rock Ferry to Hooton and had spoken to the signalmen to make sure they pulled off so we could get a clear run with "all off", we left Rock Ferry and headed up the line, accelerating nicely, as we approached Bebington station the distant for Port Sunlight was on (Caution) but in the distance the home, a tall signal, could be clearly seen showing off so the 25s were let loose and we accelerated hard, as we passed Sunlight station the up starter came into view - at danger ! - and all the anchors were dropped, brake dust, table contents, people went flying everywhere. We stopped short of the starter, it cleared and off we went - no harm done. Speaking to the bobby the next week it turns out he had got a line clear "good and early" and had pulled off the home but couldn't get the starter lock to release (he didn't know about stamping on the floor next to the lever !), he was so pre-occupied with this he forgot the train was approaching  and the home was off... happy days.

[big jim]

The 'slow pull off' is still regularly done at Rhyl on the up, you can get the colour light distant 'on' so you drop slowly down to the next signal which is a colour light 'home' approaching the platform, if that's yellow then you can expect the next signal to be 'on' which is a semaphore on the end of the platform which is the one he pulls off slowly that then takes you up to the section signal out towards Prestatyn, a few drivers have very nearly been caught out by it over the years thinking it would be off when they saw the platform end one off having missed the slow pull

 

TBH in AB sections if I get the distant on but the next signal is 'off' by the time I reach it I still take my time towards the section signal in areas of limited visibility 'just in case' its still on, if it was and I passed it then I would be to blame as the distant being on tells me that not all associated stop signals will be off

[Ray H]

Holding the Junction Protecting Signal at Danger is used so that where a divergent route has a lower speed by more than 10mph (or is outside of the speed 'bands' for MAY) than the straight on route, the train can be proven to be at the speed of the divergent route before passing the protecting signal to ensure it does not take the route at excessive speed. By holding the signal at red, the driver is forced to slow his train through the cautionary aspect sequence in rear.

 

It is used at the vast majority of divergent routes around the country

 

Simon

 

I recognise that but it is the fact that having slowed the train to a crawl/almost a stop, the junction signal is (and any subsequent and visible signals may be) (cleared to) green whereas if the junction signal cleared to a (single) yellow and the next remained at red, the forgetful driver who may have wound up the controller when the junction signal cleared to green and forgetting that he was about to take the divergent route, would still have a visual reminder ahead of him.

 

Am I wrong or is there an instruction that says the driver shouldn't be able to see a green signal beyond a red to avoid a driver unconsciously ignoring the red?

[Chimer]

This is completely fascinating to someone who up to last week had no idea whatsoever of these complexities.  So, just checking, if I did have a distant, home and starter semaphore arrangement on some future 1950s/60s layout:

 

1.  The distant should only be cleared with home and starter both clear;

 

2.  The home should only be cleared when the starter is clear, except that it can be cleared directly ahead of the train with the starter still on once the train has come almost to a stand (which implies the home must be visible from the box?);

 

3.  And as an added refinement, in this case I should clear the home slowly (better not use solenoids then!), but if the starter has cleared I can just whip it to off (was this actually an official nationwide procedure, written down somewhere in the rules, or just developed regional custom and practice?)

 

How am I doing?

 

Cheers

 

Chris

[beast66606]

This is completely fascinating to someone who up to last week had no idea whatsoever of these complexities.  So, just checking, if I did have a distant, home and starter semaphore arrangement on some future 1950s/60s layout:

 

1.  The distant should only be cleared with home and starter both clear;

 

2.  The home should only be cleared when the starter is clear, except that it can be cleared directly ahead of the train with the starter still on once the train has come almost to a stand (which implies the home must be visible from the box?);

 

3.  And as an added refinement, in this case I should clear the home slowly (better not use solenoids then!), but if the starter has cleared I can just whip it to off (was this actually an official nationwide procedure, written down somewhere in the rules, or just developed regional custom and practice?)

 

How am I doing?

 

Cheers

 

Chris

 

1 - yes

2 - yes

3 - Birkenhead area, not official just accepted - not sure if it was used elsewhere, Jim cites a North Wales example, I guess most (in the past) drivers seeing a signal being whipped off would start applying power expecting them all to come off - unless they were very close to it. Nowadays as Jim says drivers are taught if the distant is at caution then be prepared to stop at any stop signal controlled from the box, even if the preceeding ones are off.

[Junctionmad]

In the 1950 Rule Book for Absolute Block Working it was covered by Rule 39A. If you hadn't got a Line Clear so couldn't clear the Starting Signal then the Home Signal was maintained at danger until the train was at or nearly at a stand. If a berth track circuit was provided this would extend  200 yards on the approach side of the Home signal and would have to be occupied by the train before the Home signal could be cleared unless a Line Clear had been given by the next box in advance. If there were more Stop signals between the Home and Starting signals the signalman would clear each in turn as the train got to it. 

The Driver's understanding of this action was that Line Clear had not yet been received and he was being allowed to proceed at low speed subject to being able to stop at the next signal.

 

I know this, this is straight forward rule 39(a) , I have the rule book in front of me ( RCH version 1933) , what was mentioned as I understand it , is that with the starter in the loop at " off", the driver was still checked at the preceding stop signal where that preceded a low speed junction.  Thats not in the rule and may have been a local  custom ?. I personally have some  routes cleared into platform loops where the train was not checked , ( i.e. all the signals were pulled off well in advance ),  which is presumably the whole point of driver route awareness, ( and the dolly priority ) 

 

 

 

Holding the Junction Protecting Signal at Danger is used so that where a divergent route has a lower speed by more than 10mph (or is outside of the speed 'bands' for MAY) than the straight on route, the train can be proven to be at the speed of the divergent route before passing the protecting signal to ensure it does not take the route at excessive speed. By holding the signal at red, the driver is forced to slow his train through the cautionary aspect sequence in rear.

yes but I was specifically referring to semaphore usage, it this not a TCB approach control system , i.e. modern ?

Edited October 27, 2017 by Junctionmad

[big jim]

a lot of the other places ive had a 'slow pull' are in the north west/north wales (helsby and frodsham for example)

 

its something that ive not really thought about until now but in the western i've noticed i tend to get 'pulled off' quicker such as wooferton, going into the loop, the distant will be 'on' as i pass it but the diverging signal for the loop is nearly always 'off' when i sight it having bought the train down to an acceptable speed to either stop at the signal or proceed into the loop (there is no tpws overspeed fitted there iirc)

 

chimer: i dont understand the complexities of interlocking etc, i just look at what the signals say in front of me but in basic terms (as put to me in choo choo school), in order for the distant to be pulled off the associated 'stop' signals must be 'off', the signals are pulled from the furthest away first (section), then the starter which enables the distant to be cleared

 

so if on a basic 3 signal starter, home, section set up if one of the stop signals is at danger you wont physically get the distant lever to pull in the box

 

regards point 2: a train could be bought into 'station limits' (between home and section) by having the distant on and doing as you say bring the train slowly to the signal and pulling off, once in station limits the signaller could return the home to danger and (depending on local circumstance/layout) accept another train from the next box down the line up as far as his (now at danger) home signal even if the first train is still within station limits for some reason, i had this happen a few weeks back but am racking my brain as to where it was, very unusual to do it now days though

 

(prepares to be shot down!)