Construction of a Test Track

[Colin Parks]

Thanks Howard,

To be honest, the ballast is not quite as neat as the pictures suggest and there are still a few tweaks to do in that respect. The track should all be wired and the remaining switches possibly even mechanically linked by the end of next week. I am looking forward to receiving the lever frame etches, then the fun really begins!

As soon as I have mastered the inner secrets of Power Point, I shall post a provisional signalling diagram, based on your suggested solutions of how to get all of the signals and switch operation onto a 20-lever frame. Adding the trap point pictured above has made arranging the levers more tricky and the 'siding' switch on the tandem turnout will be moved from its position on the frame (where it should not have been in the first place).

All the best,

Colin

[Colin Parks]

A tentative version of the signalling diagram for the test track, with thanks to to Howard for help with the graphics.

Test Track PP Presentation # 1.jpg

It all just fits in a 20-lever frame, but I am not totally sure that the positions are ideal.

[Noel]

As platform 2 is a passenger road, the catchpoints [9] by signal 2, and the associated fpl 4 are not required. The other end of 9 can then be operated as a crossover by 7. Conversely, moving from the headshunt to the sidings involves passing 17 at danger, which is not good practice. You could add a ground signal here, or, possibly more probable, replace 17 by a conditional ground signal [yellow on, I think, in this context, a black disc]. You could also add a second disc above 12, so that a driver leaving the stabling is told which platform he is going to.

[grovenor-2685]

Do you really want Colin to unbuild the trap point he has just proudly finished?
True it is not positively required by the HMRI, but it was sometimes provided.
My personal change would be to make 7 and the right hand end of 9 into crossover 7 and leave the trap as a single ended 9.
But that's not to say its wrong as is, more of a personal preference.
Regards

[Colin Parks]

Thanks Noel and Grovenor for your observations re. the signalling diagram. This an area of railway operation that I know very little about.

It is as a consequence of changing the orignal track plan from double to single line that there is a trap point at 9. That is also why there is one trap point too many! Changing lever 7 into a crossover and having 9 just operating the trap point makes sense, and I might just change that around. It simplifies moves to and from platform 2.

The lack of a ground signal by 17 is now of concern, but adding one would require one more lever than I have spare. Another ground signal at 12 would be good, but again, there is no spare lever for this. I will have to have a good think about this.

The facing point locks will only be operating on the lever frame itself for the purpose of correct operation of the locking frame - I do not envisage having FPLs actually on the track locking the switches. Similarly, I am not sure if making operational ground signals is feasible or not given my lack of skills in the S&T department, though I will give ot a try.

Meanwhile, some progress has been made with devising a way of driving the switches with rods across the board joints. I have turned some brass bushes which locate into the ends of the boards and have been threaded 4BA to give a nice solid fixing. In the picture, the base board ends have to be imagined as being between the nuts, with 1.6 mm piano wire pushing from the shorter bush into the longer one. 20 mm of travel is needed to operate the escapement mechanism which drives the switches.

IMG_8886 (2).JPG

One drive rod has been installed and it does work as far as the second bush.

[Noel]

That's why I suggested making 17 a conditional ground signal - no extra lever involved. A conditional signal, in this context, is one that only applies to certain moves past it. In this case it must be cleared for moves from the headshunt to the main line, but can be passed at 'danger' for moves from the headshunt to the sidings. http://www.railsigns.uk/sect3page3/sect3page3.html and see page 4 for the reason the original yellow on white discs were changed to yellow on black [a bit later than I thought]. This change is unlikely to have been retrospective.

[Le Corbusier]

Thanks Noel and Grovenor for your observations re. the signalling diagram. This an area of railway operation that I know very little about.

As with so much, Ignorance is a relative term , you're way beyond me .... as usual learning loads from this Colin

[Paul Townsend]

A tentative version of the signalling diagram for the test track, with thanks to to Howard for help with the graphics.

Test Track PP Presentation # 1.jpg


It all just fits in a 20-lever frame, but I am not totally sure that the positions are ideal.

Colin and Howard, please tell us how the signalling diagram graphics were done. Is there a library of symbols somewhere?

[Colin Parks]

Hello Paul,

The image seen here has been converted to a jpeg file so that it displays on the Forum page, but the graphics were done with Power Point on a blank slide. The 'shapes' function was used to import a shape or line onto a slide then 'edit shapes' allows those elements to be altered. Using the 'zoom' at 200%, it was easy to work on the plan. Each number and line of text is in a separate text box, therefore easy to change when working on a plan such as this.

The complex parts like signals have not fully mastered by me yet, but I used some of Howard's elements with permission, copied from the initial diagram that he produced. It is like learning a very basic form of Templot and the signals were formed into a group, enabling them to be moved easily, rather than piece by piece, which is similar to the Templot 'group shapes' function. I only realised that was how Howard had done it afterwards when noticing the 'group' button.

Colin

[Colin Parks]

Hello Noel,

Thanks for the clarification of the operation of the conditional yellow signal. Would that signal then allow a train to depart from the headhsunt onto the running line up to signal 3? I shall amend the plan and see if I have got it right.

Colin

[Alan Turner]

Hello Noel,

Thanks for the clarification of the operation conditional yellow signal. Would that signal then allow a train to depart from the headhsunt onto the running line up to signal 3? I shall amend the plan and see if I have got it right.

Colin

When OFF yes.

regards

Alan

[Colin Parks]

Amended signalling diagram with conditional ground signal 17 and crossover 7

Capture.PNG

[Guy Rixon]

I presume that there is a distant for inbound trains but it is fixed. Would it help to have an outer home set further back?

[Colin Parks]

Hello Guy,

The puzzle is how to fit all the required signalling and switch control into a 20-lever frame! There ought to be an outer home I suppose, but it starts getting complicated.

Alan,

The signal at 17 would be off when passed, but that was not clear in my post. I was trying to imagine what controlled the route out of the headshunt.


Colin

[Guy Rixon]

Whereabouts is the signal box? If there is a shortage of levers, then perhaps some of the shunt moves close to the box could be made under hand signals?

[Paul Townsend]

Hello Paul,

The image seen here has been converted to a jpeg file so that it displays on the Forum page, but the graphics were done with Power Point on a blank slide. The 'shapes' function was used to import a shape or line onto a slide then 'edit shapes' allows those elements to be altered. Using the 'zoom' at 200%, it was easy to work on the plan. Each number and line of text is in a separate text box, therefore easy to change when working on a plan such as this.

The complex parts like signals have not fully mastered by me yet, but I used some of Howard's elements with permission, copied from the initial diagram that he produced. It is like learning a very basic form of Templot and the signals were formed into a group, enabling them to be moved easily, rather than piece by piece, which is similar to the Templot 'group shapes' function. I only realised that was how Howard had done it afterwards when noticing the 'group' button.

Colin

Thanks for that.
Could you PM me /email me the powerpoint slide please?

[JFS]

Whereabouts is the signal box? If there is a shortage of levers, then perhaps some of the shunt moves close to the box could be made under hand signals?

Good Grief - whatever next!

Such practices might have been acceptable on the LNWR, (who seemed not to care no matter how many accidents befell the Irish Mail* from such slack practices over the years) but never on proper railways

* For example at Penmaenmawr, 29 August, 1950 - http://www.railwaysarchive.co.uk/docsum ... ?docID=402 - reminds you just how difficult working the real railway could be.

Does the "Irish Mail" win the prize for Britain's most-wrecked named train? (Abergele, Tamworth (twice), Penmaenmawr...)

Best Wishes,

[Colin Parks]

Ah yes, I missed the signal box out. How could that have happened?!

It is situated as shown here on this screen capture (ignore the 'editable' bit - this capture is not editable):

Capture 2 with Signal Box.PNG

There is already one switch taken off the lever frame (access to the left or right hand siding), which will have a separate lever. Not sure how hand signalling would work on a model.

[Alan Turner]

Hello Guy,

The puzzle is how to fit all the required signalling and switch control into a 20-lever frame! There ought to be an outer home I suppose, but it starts getting complicated.

Alan,

The signal at 17 would be off when passed, but that was not clear in my post. I was trying to imagine what controlled the route out of the headshunt.


Colin

I'm assuming sig 3 is the section signal so 16 locks 17 when normal. Reversing 16 frees 17. you would not be required to lock either 16 or 15 to leave the Head-shunt as it is a trailing move. To get into the head-shunt you would need to lock 15N and 16R so 20 will test for that.

regards

Alan

[grovenor-2685]

I'm assuming sig 3 is the section signal so 16 locks 17 when normal.

Put correctly 16 releases 17.

Reversing 16 frees 17.

ie 17 released by 16 which is the same as above.

you would not be required to lock either 16 or 15 to leave the Head-shunt as it is a trailing move.

Actually signals are required to lock trailing points in the route and hence 17 locks 15 as well as being released by 16. However the facing point locks are not required for trailing moves hence 13 and 14 are not involved.

To get into the head-shunt you would need to lock 15N and 16R so 20 will test for that.

20 will lock 15, released by 16 and also usually released by 13 and 14. Sometimes shunt moves may omit the facing point locks but unlikely in this case with 20 as a miniature arm rather than a shunt disc.
Incidentally facing point lock 10 is not strictly required as passengers would not be run into the stabling siding.
As a yellow disc shunt signal 17 should have a yellow stripe on a black (or white) background, not a black stripe.
Regards

[Will L]

Excuse my ignorance, but couldn't the facing point locks on crossover 7 and 15 be a single lever too, rather than a different lever at each end? That would save a couple of levers.

[John Palmer]

The following thoughts occur to me:

1. There are two lockbars numbered 8, so a different lever will be required for one of these.
2. Better to employ a ground signal in the immediate vicinity of 16 Points than the miniature arm number 20 for a movement through those points?
3. No ground signal provided to control a movement into EMU stabling. After dark, how does a driver know that 12 Points have been set for such a movement?
4. No ground signals provided to control shunting movements into either platform – desirable to have these?
5. I am unclear as to the purpose of discs 2 and 11, which seem to duplicate the role of running signals 1 and 5. I'm also unclear whether 1 reads over 7 Points into the loop, or only authorises a movement straight ahead over the main running line. The layout can accommodate a passenger departure from Platform 1 over either loop or main, but the releases required for the applicable running signal will be different.

Didn't Tom Rolt comment that the Irish Mail had suffered more disasters than other named trains simply because of its longevity? In any case, the Penmaenmawr report provides an interesting illustration of the problems of working in the darkness, as well as those caused by ambiguous wording of rules.

[JFS]

The following thoughts occur to me:

1. There are two lockbars numbered 8, so a different lever will be required for one of these.

Why? It was not uncommon for one lever to work more than one lock - especially when levers are in tight supply! Albeit that the S&T techs would be cursing the arrangement every other week...

2. Better to employ a ground signal in the immediate vicinity of 16 Points than the miniature arm number 20 for a movement through those points?.

But that would create a "Running Dummy" which would have to be cleared for every train arriving into P 1 - and requiring the Home to be Released by it. It could be done - there were two such signals at Bude, and there is one on St Merryn - but it is not essential at what is quite a small layout especially since it is necessary to back out to the Homes for other moves in any case.

3. No ground signal provided to control a movement into EMU stabling. After dark, how does a driver know that 12 Points have been set for such a movement?

I think you will find that is the purpose of signals 2 and 11? Though these might also read to the Main via the loop - in which case they would lock points 15 EW.

4. No ground signals provided to control shunting movements into either platform – desirable to have these?

12 provides this function from the siding whilst the homes provide it off the Main. Bearing in mind this is a Southern Railway Layout where only single ground signals existed - so 12 reads 2 ways.

5. I am unclear as to the purpose of discs 2 and 11, which seem to duplicate the role of running signals 1 and 5. I'm also unclear whether 1 reads over
7 Points into the loop, or only authorises a movement straight ahead over the main running line. The layout can accommodate a passenger departure from Platform 1 over either loop or main, but the releases required for the applicable running signal will be different.

I don't know what might lead you to think that - the functions seem clear to me - as described above.

Didn't Tom Rolt comment that the Irish Mail had suffered more disasters than other named trains simply because of its longevity? In any case, the Penmaenmawr report provides an interesting illustration of the problems of working in the darkness, as well as those caused by ambiguous wording of rules.

I think you are right, but in terms of "disasters per year" it was still by far the worst! And the LNWR practice of operating crossovers with two levers whilst not providing shunt signals - even at horrendously complex locations like Preston - seem utterly perverse. The confusion at Penmaenmawr is good example of the potential result - especially in the circumstances as you describe.

Just also to mention that the FPL (10) out of the siding seems to have appeared by accident - 10 I think, refers to the Trap. (Catch Point if Martin Wynne is looking in )

Best wishes,

[JFS]

It could be that the answer to the combining of FPLs to save levers lies here:-

Butterfly.jpg

For those not familiar, it is a "Black's Patent Butterfly Pattern Economical Facing Point Lock". I took that photo last year in Sri Lanka - where there is much to interest signalling enthusiasts! But they were used by some UK railways - including the LBSC - though they were by no means common.

The 70 lever frame I recently built for Leeds city Junction, and illustrated elsewhere in the forum, does not include a single FPL lever (though there is one lever-worked Fouling Bar). Thank goodness... it simplifies the locking a fair old bit!

Best wishes,

[Noel]

No ground signal provided to control a movement into EMU stabling.

I am unclear as to the purpose of discs 2 and 11, which seem to duplicate the role of running signals 1 and 5

Like Howard, I rather thought that 2 and 11 were there for movements to the stabling line, with 1 and 5 for moves to the main.

I'm also unclear whether 1 reads over 7 Points into the loop, or only authorises a movement straight ahead over the main running line.

It could be either, depending on what actually is the 'main line' in the outbound direction. In reality, the drivers would know the answer to this. However, if the loop is to be used for running round trains to/from the headshunt/sidings, then it would perhaps make life simpler if 1 read to main via the loop.

Better to employ a ground signal in the immediate vicinity of 16 Points than the miniature arm number 20 for a movement through those points?

I'm afraid I don't quite follow Howard's comment, not being familiar with the examples he quotes, but it seems to me that this suggestion would mean that 19 would have to be cleared for all inbound trains approaching points 16, so 19 could only lock 16 in whichever position it was in at the time, and 16 could not lock 19 at all. A passenger train driver approaching 16 wrongly set would get no warning until he saw the disc. With 20 where it is, drivers approaching 18/19/20 will know immediately what is happening, and the signalman can apply a human 'approach control' on 20 to control the speed of trains if needed.