Signals - Present-Day Semaphore, Lights and Repeaters

[The Stationmaster]

Another example from Reading in the form of the second iteration of R138 which replaced the original in the 1990s when a scissors crosover replaced the facing crossover immediately beyond Caversham Road underbridge.  this signal is typical of its tome complete with 'phone on a separate post and railings around it whereas its predecessor was at the foot of the platform ramp.

 

This signal, or more correctly its predecessor was interesting in that its Position 2 JI  initially took a  train to the right, over the facing crossover onto the Up Relief Line, before heading from it to the left and across the Main lines Main to the Down Westbury Line as their was no facing connection towards it from the Down Relief Line.  The Position 1 JI read through a separate left hand 'ladder' of crossovers a bit further west, to the Down Main Line.  all of that was duly sorted when the layout was altered in the 1990s  and the connection to the Westbury lines was moved from the Up Relief to the Down Relief.  (That was the only change impleneted from all of those proposed by the Reading Track Layout Review Group that I was a member of in the early 1990s.  Various other things we had propdsed were incorporated in the main. Reading scheme of the 21st century - but no, we didn't propose teh flyover, too expensive).

 

[Michael Hodgson]

17 minutes ago, The Stationmaster said:

From 2003 a typical WR installation of the mod 1960s albeit with a couple of updatings such as the number being changed from WR black on white to BR standard white on black (early 1990s) and the original 'phone cabinet replaced by a mpre modermn one.  That apart it is reasonably typical of what happened with Reading resignalling as it has the second style of Reading design cast base to locate the post, Reading proportioned post and Reading design ladder and safety loop.  What gives a clue to its age and the scheme under which it was installed are the use of an SGE multi-aspect head (the Reading scheme seems to have used what was in the stores plus obviously some new purchases so signal heads varied with originally a mixture of Westinghouse and SGE running signal heads plus SGE ground position lights at Reading but Westinghouse at Didcot.  And of course it is WR numbering so it is clearly a Relief Line siganl (1XX series) and  an Up direction signal (odd number).  Tilehurst.   (Signal is still there but the head is now a Dorman head, post and base now nearing their 60th birthday proving that colour light signals can have long lives)

 

 

BTW I hope people don't mind all the detail but hpefully it will aid modellers who are articularly interested in gettng signals details correct for place and time)

TPWS grid a later addition, and you can tell from the moss growing on the north side of the post that the SPT is also more recent.  Disconnection boxes nearby.

[phil_sutters]

6 hours ago, Michael Hodgson said:

 

The platform on that bracket doesn't look ideal for anybody working on the signal - you'd have to squat at floor level to fiddle with the innards as its position is by your boots.  Not that I imagine it needs much maintenance.  Excellent photo, but it's plated TLW 10 & 12, not 1o & 11 as per the caption by the way.

Now corrected. Thanks for pointing out the error. I am always happy to put things right.

[iands]

1 hour ago, The Stationmaster said:

... and the original 'phone cabinet replaced by a mpre modermn one... 

 

Originally initiated in late Railtrack years and carried on into the early NR years, there was a drive by the Telecoms to eradicate the older style signal box Telephone Concentrators  and Selective SPT cabinets with modern electronic "PABX" type switches. This meant that the older style "selective calling" type SPTs need changing out for modern "CB" type SPTs  as shown in the photo. 

 

To echo Mike's other point for modellers of the "modern scene", who are particularly interested in getting signal details correct for place and time, the old "selective" type SPTs had all gone from the network by about 2010, and that most SPTs are now located at the end of a drivers walkway rather than being mounted on the actual signal post (a SPAD mitigation).

[Coach bogie]

Northallerton. Down Main reverse working signal Y476 with theatre route and caution light .Old style builds rather than LED. Replacement bracket cause by platform extension, though with a slight droop.

 

Mike Wiltshire

[keefer]

5 hours ago, iands said:

I think that is why the LED type signals have an "eyebrow" (top left) of 8 or so LEDs angled towards the track to help drivers see which aspect is being displayed when the "loco" is stood close to the signal.

I would've had no idea about this but going back to @phil_sutters post about Lewes, several pics show this (also as metioned by @The Stationmaster aspect not visible from a certain angle or because of 'strobing'):

 

Phil Sutters' post from earlier

 

You seem to have the main 'squared-off' matrix of LEDs but a top line of LEDs which follow the curve e.g.:

[Coach bogie]

One that amuses me is Northallerton Up. Since switching over to York signalling centre there is often a delay in setting up the signal route which results in the feather illuminating first prior to red changing to green. The green is already set up on the relief line seen in the distance

 

Edited May 14, 2023 by Coach bogie

[keefer]

i've read on here before that that is how some signals work, in that the signals show the process involved - there is 'thinking time' between say: red > red with feather > green with feather i.e. the feather has to prove lit before the main aspect will change.

[SZ]

3 minutes ago, keefer said:

i've read on here before that that is how some signals work, in that the signals show the process involved - there is 'thinking time' between say: red > red with feather > green with feather i.e. the feather has to prove lit before the main aspect will change.

Isn't that the basic rule, route is set before signal cleared.

[david.hill64]

On 14/05/2023 at 07:27, The Stationmaster said:

 The branch was also used to research the problem and it was found that because of the design of their suspension - intended to give the smoothest possible ride - they spent a lot of time running with various wheels not making continuous contact with the railhead.

Mike, Are you sure that was the conclusion? The issue with 14X and 15X not activating track circuits is usually ascribed to the superior wheel-rail interaction characteristics of these vehicles compared to the DMU's they replaced. The later designs lost much less energy at the wheel-rail interface than the older designs: hence lower wheel wear/ lower rail wear and better ride. The downside is that if you are not scrubbing the muck off the rail head you run the risk of not shunting the track circuits as the resistance is too high.

David

[Mike_Walker]

Also it should be remembered that Pacers of the 143 type spent many years working the "triangle of doom" based on Exeter (Barnstaple, Exmouth and Paignton) in the privatised era without any issues arising plus the 142s returned for a few years at the start of this century.

[Michael Hodgson]

7 hours ago, SZ said:

Isn't that the basic rule, route is set before signal cleared.

Yes, if the junction indicator fails to illuminate, it would be a wrong side failure for the main aspect to clear with the route set for divergence - the speed restriction over the junction may be considerably more severe than the main line; that could result in a train passing the signal overspeed for divergence.  So the locking is designed to prove the JI alight before the relay controlling the signal aspect will pick up. 

 

Similarly there can be an observable delay between a signal changing from R to Y and the signals in rear stepping up fro Y to YY and from YY to G.  This is visible where you can see all the affected signals on a long straight stretch of line. 

 

This delay between the feather lighting and the aspect clearing seems to be of the order of half a second to a second - but note that this applies to relay based interlocking and traditonal filament lamps.  LED signals and electronic locking operate a lot faster and I have not noticed any delay.

 

 

Red plus feathers is normally only a transient state, and it's a fault if it stays like that - although it could also be correct if there were a call-on subsidiary, when the sub is cleared.

[St. Simon]

20 hours ago, The Stationmaster said:

What do you do while waiting for the pub to open for your OFs get-together?  Well if you know what you're looking for and know where it is in railway terms you could try to find your way to a footbridge that you know is near it - so I did.

And here it is in all its 21st century  glory (2017 to be precise) - a standard SR disc elevated on a lattice post for a setting back movement off the Ascot line towards Wokingham station but alas insufficient magnification on the camera for the best view .  But I didn't worry about that as I have earlier photos of it taken from a passing trains so all I really wanted to do was find out if it was still there.

 

 

 

 

 

Hi Mike,

 

It's still there (along with the disc coming out of the turnback), although critically endangered due to the resignalling, I keep meaning to go down and get a photo!

 

Simon

[Mike_Walker]

Something not mentioned up to now is the reappearance of "splitting distant" signals in recent years.  This example is T1624 (formerly UR30B as shown here) on the Up Relief approaching the Ruscombe crossovers.

 

 

The left hand 3-aspect head shows Y-G-Y and the right hand one R-Y-G-Y.  If a train is to be routed along the Up Relief then the appropriate proceed aspect appears in the left hand head and the right is dark.  If the train is to cross to the Up Main at Ruscombe the the left head is dark and the proceed indication appears in the right head.  When the signal is at danger, as here, the left head is dark and the red in the right head illuminated.  

 

There is a very short distance between this signal and the next T1672 (R179) which is right by the junction and carries the position 4 feather for the crossover.   In this view it's hidden by the other bracket signal and the Up train but you can see the position of the crossover under the forward part of that train.

 

There are several of these on the GWML, including approaching Airport Junction on the DM and Tilehurst on the UM.  However, they seem to have fallen from favour for new works with primary route indicators being preferred.  Incidentally, even when converted to LEDs they have to retain independent lens to maintain an unambiguous indication.  Even at night, the driver's route knowledge tells him which route he will be taking by the height of the green or yellow lights.

 

Sorry it's a bit distant (ouch) but I was shooting the trains rather than the signal.

 

[St. Simon]

5 minutes ago, Mike_Walker said:

However, they seem to have fallen from favour for new works with primary route indicators being preferred.  Incidentally, even when converted to LEDs they have to retain independent lens to maintain an unambiguous indication.  Even at night, the driver's route knowledge tells him which route he will be taking by the height of the green or yellow lights.

 

Hi,

 

The use of a Splitting Distant isn't 'falling out of favour', the choice of the junction signalling method is based on several options rather than just 'preferring' one method over another. See my book for the reasoning and rules around it.

 

I would be contributing to this thread, but I'm planning on launching a whole external blog about signalling, photos, explanation etc in the very near future, so I'm keeping all my content to myself :)

 

Simon

[St. Simon]

9 hours ago, Coach bogie said:

One that amuses me is Northallerton Up. Since switching over to York signalling centre there is often a delay in setting up the signal route which results in the feather illuminating first prior to red changing to green. The green is already set up on the relief line seen in the distance

 

 

Hi,

 

Perfect demonstrates the switch between a Route Relay Interlocking and a Computer Based Interlocking. In an RRI, the junction indicator proving would be almost instant, where as a CBI takes longer to process the proving etc, meaning a route indication can be illuminated for a few seconds before the signal clears.

 

Simon

[Mike_Walker]

A slight correction to my previous post - I'm surprised @St. Simon didn't pick it up!

 

When the route is cleared for the Up Relief the right hand head is not dark but shows a single yellow (but in the top lens not bottom as normal).  This can be seen below which also shows the next signal T1672 (R179) with the feather.  Presumably the reverse is the case if the crossover is set to the UM.

 

[Rugd1022]

Banbury when it was a nice mix...

 

 

 

 

 

 

[ruggedpeak]

11 hours ago, keefer said:

I would've had no idea about this but going back to @phil_sutters post about Lewes, several pics show this (also as metioned by @The Stationmaster aspect not visible from a certain angle or because of 'strobing'):

 

Phil Sutters' post from earlier

 

You seem to have the main 'squared-off' matrix of LEDs but a top line of LEDs which follow the curve e.g.:

Hopefully all this was covered off in robust testing and specifications and design but the use of one lense with various colours that may only occur to those brought up in an analogue world.

 

A traditional 3/4 aspect had a positional element to aspects that could assist in identifying issues e.g. red green and amber were always in set positions relative to each other and the signal head so gave an additional dimension to the processing of what was being seen. During aspect change there was also a visible positional change.

 

Ghosting of a different colour was presumably impossible - a red signal could not appear green, and if it did the positional issue above kicks in e.g. a green being perceived at the bottom of a 4 apsect should trigger a query in a driver's mind.

 

These are lost with a multi-coloured single lense installation. Will be interesting to see whether these are safe in the 'real world' and what lessons get to be learnt.

[Mike_Walker]

Q:  When is a signal not a signal?

A:  When it's a Points Indicator.

 

This example at Bourne End, and the one in Down direction, appear as fully fledged signals but technically they only show the route is correctly set.  The Stop board takes priority - you have to be in possession of the token (to Maidenhead) or staff (Marlow) before setting off.  The route indicator shows M (Main) to go to Maidenhead and B (Branch) for Marlow.

 

 

 

However passing them at danger is still a SPAD!

 

[Mike_Walker]

8 minutes ago, Rugd1022 said:

Banbury when it was a nice mix...

 

 

These two were late arrivals at Banbury.  They were at the London end of the Down platform and were previously ground discs.

 

They came about as part of the Reading rebuild.  When GWR wanted to divert some of its trains via the Chiltern line they had to reverse at Banbury.  Technically, therefore under the old arrangements the passengers had to detrain at the Down platform and cross the bridge to the Up whilst their train reversed in the goods loop beyond the North Box before returning to pick them up.  This displeased Mr Hopwood severely so following an investigation it was found the two discs could be replaced simply and "cheaply" (by railway standards) which not only allowed the diverted trains to reverse at the platform but also made the station operation more flexible for regular Chiltern and GWR services.

 

The disc at BS33 was for access to what was then a siding but today is the Banbury Light Maintenance Depot

 

The whole mod was, I understand, charged to the Reading project.  A win all round.

[Wickham Green too]

48 minutes ago, Mike_Walker said:

... This example at Bourne End, and the one in Down direction, appear as fully fledged signals but technically they only show the route is correctly set.  The Stop board takes priority - you have to be in possession of the token (to Maidenhead) or staff (Marlow) before setting off. ...

Since the invention of Token or Staff working of single lines it has always been a requirement to be in possession of the Token or Staff ( or Ticket ) before entering the section - so how does this differ ?

[Mike_Walker]

We had Stop signs like that at BE when the points were simply worked by a manual lever frame.  That was replaced by powered points worked from a Ground Switch Panel and the signals, sorery, points indicators were installed as part of that.  As they are not technically signals it's the wording on the Stop board that takes priority.

[Michael Hodgson]

2 hours ago, Mike_Walker said:

Q:  When is a signal not a signal?

A:  When it's a Points Indicator.

 

This example at Bourne End, and the one in Down direction, appear as fully fledged signals but technically they only show the route is correctly set.  The Stop board takes priority - you have to be in possession of the token (to Maidenhead) or staff (Marlow) before setting off.  The route indicator shows M (Main) to go to Maidenhead and B (Branch) for Marlow.

 

 

 

However passing them at danger is still a SPAD!

 

It's still a signal - it's only the square box is a junction indicator.

 

As for the Stop board taking priority, it's the same ptinciple as the rule used on countless single lines over the past century that you can't proceed wtihout the staff/ticket/token, even if you have the signal.

 

The only difference is that in order to avoid ambiguity  the signalman would not (and in recent times could not) pull off the signal until he had obtained consent from the far end of the section and obtained the token that he is about to hand over to the driver;  a stop board cannot be pulled off of course - the equivalnt is obtaining permission according to the instructions on the board.

[Rugd1022]

3 hours ago, Mike_Walker said:

These two were late arrivals at Banbury.  They were at the London end of the Down platform and were previously ground discs.

 

They came about as part of the Reading rebuild.  When GWR wanted to divert some of its trains via the Chiltern line they had to reverse at Banbury.  Technically, therefore under the old arrangements the passengers had to detrain at the Down platform and cross the bridge to the Up whilst their train reversed in the goods loop beyond the North Box before returning to pick them up.  This displeased Mr Hopwood severely so following an investigation it was found the two discs could be replaced simply and "cheaply" (by railway standards) which not only allowed the diverted trains to reverse at the platform but also made the station operation more flexible for regular Chiltern and GWR services.

 

The disc at BS33 was for access to what was then a siding but today is the Banbury Light Maintenance Depot

 

The whole mod was, I understand, charged to the Reading project.  A win all round.

 

I know Mike, our depot covered soemeof the diversion work, conducting other drivers over the Chiltern, turning back at Aynho and Banbury etc. I remember while learning the Chiltern a mate and I stopped off at P.Risborough and spent two hours in the model shop not far from the station, my mate bought a rather large G Scale German 2-8-2T loco and had to carry it home!

 

One of my favourite signal structures on the routes I sign - the old GWR gantry at the London end of Oxford station, now long gone of course and much missed, I've climbed up it a few times to take photos at night with my train stopped on the Up Main, it used to wobble about in high winds...

 

 

A couple more from Banbury...