Advice sought on a few signalling questions.

[59004 ( was Shedcombe....)]

Hi all,

 

For my layout, that I will introduce once this signalling issue has been cleared, I have a few questions, with regards to the signals to be used at the ends of the platforms.

What options do I have?

What approach/choice is best/most appropriate?

 

Recently, I did get advice from Nick Goward (of Coastal DCC) for the correct signalling of the layout, bearing in mind which running/routing is desired over the tracks. We went over all necessary signals, but we have not talked about it in terms of block sections. Upon finalizing the track (signalling) diagram, I've come to the conclusion that I would like the have the scenic section of the layout regarded as one block. The block Ironbridges Interchange (Junction) Station. You can see on the attached diagram, what it looks like, where what types of signals have been designed in (basically all 3 Aspect, with the occasional add-on bits if necessary, and one ground signal).

As I've now basically chosen for a junction block with the station included, as the junction extends from before the station to past the station, I still have a few questions to ask.

Question 1
Is it appropriate to have a junction and/or a station being a block by themselves, being within a block, but still with more signals within that block, or is this impossible?

Question 2
Bearing in mind that I'd like to be the station to be within a block, its signals on S and the Platforms 1a, 2a, 2b, 3b and 4b are all within that block and mainly intended as Starters for stopped trains. These signals were drawn in, in the sense of a signal within a chain of signals along a line, drawn in as all the others, 3 Aspect, but where appropriate extra with a feather for taking the diverging route at the junction. I suspect with the feather lit, the logical aspect on would then be yellow?

Question 3
Would it be possible, or even preferred/more logical, to have the platform as pure 2 Aspect Starter signals, with a feather for the diverging route?

Question 4
Could such a signal also be made up of two 2-aspect heads side by side, showing green only on the head for the intended direction?

Any other advice and/or options greatly appreciated.
Please keep in mind, this is South-London 1967.


Regards, Michel

 

 

 

[dave55uk]

Hi Michel.

 

Aside from the track layout being a little strange ;-) , all looks okay, except:

 

Coming in from E and F, you have the feathers the wrong way round on both signals, and,

Exiting via G and H, I think the two signals are too close to the preceding points. Whilst sometimes they were placed like you have them,

I think they are too close to the signals on platforms 3b and 4b.

 

Hope you're keeping well,

Dave.

[TheSignalEngineer]

I'm not quite sure what your interpretation of "Block" is in this context. As it is south London 1967-ish are we talking worked from a local box or a panel provided on an MAS scheme? I would expect by that time the lines would be worked under Track Circuit Block Regulations, so the "Block" would be signal to signal. my signal comments would relate to approximately BR standard principles at that time although there were lots of regional variations still in use. The Southern also had a lot of places where there were colour light signals on the main lines, but shunts were done with solenoid discs.

 

Regarding the layout of the tracks, is there any reason why the Up Fast and Up slow could not be transposed to the right hand end (E and F). This would mean that Up trains do not have to cross each other on approach to the station.

 

As Dave says the feathers on the signals E and F need to go the opposite way to what is shown. The signals going away from the junctions need to be a train length clear so that trains going to C, G and H do not foul up the whole layout if they are stopped at the signal.

 

The turnback signal would have a Theatre indicator showing F or S rather than a feather.

 

The platform signals should be a three aspect operating to the normal sequence, as they will need to show a yellow if the next signall is at red. They can show green with the feather lit and the next signal 'Off', but routes requiring the feather should be approach released if the speed difference between the routes is more than 10MPH. Colour light signals with multiple heads rather than route indicators would be extremely unlikely if at all.

[caradoc]

Is there a particular reason/justification for transposing the 4-track layout from paired by direction on the right to paired by speed on the left ? On the real railway, on a route busy enough to need 4 lines, having every train on the Up Slow block 3 of the 4 lines when passing through this station would be a huge operational inconvenience.

[Grovenor]

I would provide "Call on" aspects on the signals coming in from E and F to allow a short train into 2b with 2a occupied, also the signal from 2b to the siding should be a "Shunt" not a "Call on". Otherwise as per The Signal Engineer.

Regards

Keith

[RailWest]

I too am very confused as to what the OP means/understands by a 'block' in this context. I'm surprised that one can talk about "all necessary signals" without having determined your block section limits.

[The Stationmaster]

I too am very confused as to what the OP means/understands by a 'block' in this context. I'm surprised that one can talk about "all necessary signals" without having determined your block section limits.

Although it was not made clear I did wonder if it might be something to do with DCC?  It clearly isn't anything to do with a block in the signalling sense as there are at least two signal sections on every through line although I presume some of the signals might be off stage.

 

Incidentally it is worth pointing out that in some cases illuminated discs are more likely to be used than position lights although it is not spelt out if this is assumed to be new (i.e. new in 1967) signalling or earlier signalling still extant in 1967.

[59004 ( was Shedcombe....)]

Thank you all for the responses.

 

The 2-H Thumpers are running from the righthand side lower FY on to the UP Slow, passing the righthand side tunnel and the junction signal with the feather OFF, as it's the most logical route, arriving in to Platform 2A to terminate. They continue to the Headshunt S by passing the gantry signal with call on/shunt light LIT. They reverse back out to Platform 2B passing the ground signal and depart, with the signal with the feather LIT, to the DOWN Slow, through the tunnel, and by junction off the DOWN Slow, back to the lower FY.

 

The UP Fast trains exit the righthand side tunnel, passing the junction signal with the feather OFF, as it's the most logical route, staying on the FAST in to Platform 1 and departs through the tunnel on the left hand side, passing 2 signals.

 

The UP Slow trains also run as the 2-H Thumpers in to Platform 2A. They depart passing the signal, crossing the DOWN Fast, and in to the lefthand side tunnel, passing another signal in front of it.

 

The DOWN Fast trains exit the lefthand side tunnel, passing a signal protection the crossing with the UP Slow, in to Platform 3. Departure is by signal with the feather OFF, passing by the crossovers, another signal in to the righthand side tunnel.

 

The DOWN Slow trains exit the lefthand side tunnel, passing a signal in to Platform 4. Departure is by signal with the feather OFF, passing by the crossovers, another signal in to the righthand side tunnel.

 

The UP Semi-Fast trains exit the righthand side tunnel, passing the junction signal with the feather LIT, changing over the crossovers from FAST to SLOW, in to Platform 2A and continue as the UP Slow trains do.

 

The DOWN Semi-Fast trains run as per the DOWN Slow trains in to Platform 4. Departure is with the signal feather LIT, changing over the crossovers from SLOW to FAST, and continue on the FAST as the DOWN Fast trains do.

 

Here's the revised signalling diagram (also changed the signals from 3 Aspect to 4 Aspect), as well as the trackplan with drawn in signals and gantries. I appreciate your views and comments on them. The righthand side has an alternative version, as I'm not 100% sure about the gantry for the signals from the righthand side tunnel to the crossovers. I've you have alternative thoughts and ideas, please share them. The signals are all 900 mm left of the track centre line (on gantries or above the tunnel mouths) or 900 mm left of the same line, as line of sight, in case the track curves off to the left (on normal masts/poles).

 

The grey tracks are temporay, only showing the alignment inside the tunnels, in view of the line of sight towards the signal positions. The dignals show as a symbol, with a point at the rear. A feather is attached, as is the Call On/Shunt signal.

 

Regards, Michel

 

 

 

 

[Grovenor]

Looks to me like the new plan has all the problems of the original and you have ignored all the advice. Your prerogative of course!

Is the track already fixed and unalterable? If not then I would try to work in a bay platform for the terminating trains and eliminate the siding and the traffic bottleneck. And I would try and get the first facing turnout further from the tunnel on the right hand side, as it is the signals would have to be sited in the tunnel.

Simple straight post signals would be used where possible, gantries only when there is no alternative, at the most you need only one gantry, for the Up fast signal coming from F.

Regards

[59004 ( was Shedcombe....)]

Hi Keith,

 

The trackplan is not new, but shown as it already was. The signal diagram is not showing a "block" anymore with signals within it, as that's technically incorrect. It's indeed a MAS signalling scheme and now shows as what the station (AND junction) area is, which is also the scenic area of the layout. I have altered the signals from 3 Aspect to 4 aspect, as per given advice. I'd still like to guard the tunnels with signals and also prefer this amount of signals on the layout, so I've decided not to take any off, even if they are relatively close to each other and to close to be fully prototypical. A layout is often compressed anyway.

 

The width of the brick bridge the railway runs on, is 27 mm wider either side of the outer track centres. The safety wall on it is 7 mm wide and starts 20 mm from the same track centres, as per loading gauge dictation. As the centre line of signals have to be at least 27 mm from the track centres, as per the same loading gauge dictations, signals can't simply be on posts on the outside of the outer tracks. As the standard track centre to track centre is 52 mm a post can not be in between such tracks either, only where they are space wide enough for this. Therefor I've used the gantries, partly also advised by Absolute Aspects. Besides, I like how nice and interesting they look on a layout.

 

As for the bottle neck, yes it is there on purpose, and not to go. Even if it weren't for the terminating and reversing thumpers (chosen for the interest in operation), it would still be a 4-track mainline splitting in to two seperate 2-track mainlines, thus a junction being a bottleneck (aren't they all, if they are without flyovers?) and at the same time a(n interchange) station as well.

 

The points can't be moved, as they just fit within the board sizes. The station can't get wider nor longer, can't take 5 tracks and wider platforms and only 3 through tracks would make it more a bottleneck as it's now. Nothing wrong with modelling a bottleneck IMHO. Railway networks are full of them, and operation is far more interesting to look at as just plainly freely passing trains, each on their own unhindered dedicated routes and reserved tracks.

 

To make the signal positioning possibly a little bit more prototypical, I could probably have some post/gantry foundations on the outside of the walls of the railway structure (as a form of prototypical afterthought) and replace the signal of Plaform 4 with one on a post and have a gantry from the outside of the UP Slow curve of E and F and have a similar gantry here as will be at Platform 2B and 3. A similar solution with the signal at Platform 1 is not possible, because of the bridge. The sigals at Platform 2A, Platform 3 and the signal from E can be on top of the gantry (as per SR preference?) or on the vertical post of the gantry (of course 27 mm outside of the track centre and not the 11.85 mm (900mm in real life) as they are drawn now.

 

Regards,

Michel

[Grovenor]

 

I have altered the signals from 3 Aspect to 4 aspect, as per given advice

That advice does not seem to come from this topic!  It does perhaps give a bit of an excuse for the closely spaced signals. But the platform starters protect the tunnels anyway and no way would you want to start a train just to stop it at the tunnel mouth blocking the whole station throat.

Regards

[59004 ( was Shedcombe....)]

As I've set my mind on signals at entering and leaving the scenic section as well as of course the ones needed at the station, I've settled on 15 signals, incl. the one at the buffer stop.

The signals are preferably next to the track on standard posts, where possible on brick structures to elimate the need to use posts or on gantries over the tracks where a straight post was not possible.

 

I hope it is and looks prototypical enough, besides my own preference to use this amount of signals and the limited spacing between them and some other layout/track elements. The signals are also positioned such, and likewise angled, that it helps line of sight for oncoming trains but also allows all signal aspects to be viewed from the front of the layout.

 

There are two 4-aspect signals on standard posts, one 4-aspect signal on standard post with right feather, one ground signal and one buffer stop (red signal) light.

Three gantries, are all for two signals, one lower down on the post for the adjacent track and one on the gantry for the track next to it, with 45 degree angled steps to the level section of the gantry.

One gantry is with a 4-aspect signal left feather and a 4-aspect signal righ feather, one gantry is with two 4-aspect signals left feathers and one gantry is with a 4-aspect signal and a 4-aspect plus shunt signal.

There are four 4-aspect signal heads, mounted on the walls next to the tunnel mouths.

 

Regards, Michel

 

 

[59004 ( was Shedcombe....)]

Stubborn as I am, I've set my mind on using the following signals and positions.

For me, the signalling this way is close enough to reality.

 

Regards, Michel

 

 

 

 

[The Stationmaster]

Michael I see from the post above that some of the signals are not in the correct place in relation to pointwork.  Having the signals on the approach to the tunnels is your choice but getting those protecting pointwork in the wrong places is going to look far from good.

[59004 ( was Shedcombe....)]

Hi Mike,

 

My excuse for the 2 on the righthandside is the fact that they need to be that far away from the tunnel mouth, to be well visible enough above the tracks.

If I were to move them further to the right, not only can't the drivers see them properly, the layout viewers cant either.

I'm happy with them as they are now situated, even if a tad unprototypical.

Besides IMHO, routeknowledge can also involve knowing that the signal is position "a little"  late, and a need to stop well before it, maybe even with a marking of that point at track level.

 

Regards, Michel

[beast66606]

Hi Mike,

 

My excuse for the 2 on the righthandside is the fact that they need to be that far away from the tunnel mouth, to be well visible enough above the tracks.

If I were to move them further to the right, not only can't the drivers see them properly, the layout viewers cant either.

I'm happy with them as they are now situated, even if a tad unprototypical.

Besides IMHO, routeknowledge can also involve knowing that the signal is position "a little"  late, and a need to stop well before it, maybe even with a marking of that point at track level.

 

Regards, Michel

 

It's not so much to the left or right of the track, it's in relation to the s&c (switches and crossings) - for example in the second diagram (of your 20:44 post) the purpose of the ground signal is unclear and the 4-aspect with shunt is beyond the toe of the points it controls, a driver can technically (although with defensive driving it's not so common except on some passenger routes) drive right up to the signal - if your little drivers did that the points would be locked by the trains standing on them.

[59004 ( was Shedcombe....)]

Hi Dave,

 

The orange track is the headshunt / turnback stabling track, as can be seen in the first diagram. The ground signal is to release trains from it. Yes, some signals are a bit off standard positions, too far up the lines. The signals at the platforms are at their chosen positions to give maximum usage of platform length. The feathered signals at the righthand side tunnel are positioned so their good viewing exiting the tunnels as well as for the layout viewing from the front. As with all "non-standard" things, how to react/act upon, comes with the driver routeknowledge training. So no stepping on toes, not even on the ones of points .......

 

Regards, Michel

[beast66606]

Hi Michel,

 

It's your layout but the rules of the railway will not permit signals to be in advance of the point toe - no matter how much driver training is involved.

 

Your choice.

[59004 ( was Shedcombe....)]

Ah well Dave, will not be the only detail rule 1 applies ..... Thanks for all input, from everyone.

 

Regards, Michel

[RailWest]

Well, I can think of many historical examples of stop signals which were placed almost immediately in advance of trailing point toes, but the crucial fact was that those points would be protected by the stop signal next in rear.

[59004 ( was Shedcombe....)]

Not completely sure what you mean with that Chris.

Can you enlighten a little please, or better even, supported with a drawing or pictures?

 

Regards,

Michel

[RailWest]

Well, take for an example this view of Masbury.

 http://www.archive-images.co.uk/image/3697/Masbury+stn+c1964.jpg

The Down Starting, on the left, is right at the toe of the down line end of the crossover. The crossover was protected in the down direction by the Down Home, some distance back behind the photographer.

[Grovenor]

But that is a totally different scenario, similar to the signals Michel has put in for entering his tunnels. The ones under discussion are the facing junction signals located well past the toes of the points they are reading over, in reality they would be inside the tunnel, or if it is not too long at the other end of the tunnel. They also still have the JI feathers swapped right for left as per one of the very first comments. I see why Michel has done that although I wouldn't where I decide rule 1 issues.

Regards

[59004 ( was Shedcombe....)]

All clear gentlemen.

 

I know it's not prototypically correct, but then again, for instance, the crossovers rights at the platform ends would normally be positioned a little further from the platforms.

Now it can't happen, because of the board ends AND the control servos that can be under the tracks inside the brick structure but not under the road bridges.

The tunnels are supposed to be about half a mile long each, with the junction for the Thumpers right after these tunnels.

Therefor, with the signal at that junction at yellow plus lit feather, the Thumpers will leave with the signal at tunnel entrance at double yellow.

What's the logical signal at Platform 2B for departure?

Also double yellow with lit feather, I guess?

 

Regards, Michel

[phil-b259]

I see why Michel has done that although I wouldn't where I decide rule 1 issues.

 

Indeed.

 

Michael is of course perfectly entitled to invoke rule 1 - after all the model is built for his enjoyment*, BUT it needs to be made crystal clear to other views who might wish to replicate his design (in full or in part) that this is the case. While Michael's design may use British style signals, their placement is quite simply not be remotely acceptable to any organisation (be they designers, or safety regulators) were his plan to be used in signalling a real UK railway.

 

It is an unfortunate fact that many modellers do not signal their layouts to comply with the fundamental principles that apply such matters and while this can be for many reasons, it is important that if the choice is taken to disregard such principles, the fact that is a deliberate choice is made clear.

 

* I'm afraid were it to be exhibited then I would be unable to enjoy it, however good the modeling - far too many unrealistic signalling ideas for someone with professional involvement in such things.