Signals for Glenmutchkin

[LNERGE]

Here's a full set of drawings for North Walsham. Latterly it was key token but i've managed to backdate thing's a bit to when tablet working was used..(1978)

 

 

 

 

 

Edit to add colour shot of box diagram here..

 

http://www.flickr.com/photos/pwayowen/6986046134/in/set-72157627782450647

[The Stationmaster]

The interesting question about North Walsham is when the locking dates from (noticing that the signalling has more modern features such as berth track circuits at the Home Signals and colour light distants as well as considerable track circuiting)?  In that situation I can see no problem with 13 locking 3 as there would by then (1978) be no requirement to have the facing point locked before accepting a train and in any case the presence of the berth track circuits suggests there were possibly further controls on the token etc circuit.  

 

But in earlier times the crossing situation would have been subject to the problems I have outlined above although in this case because of 16 being motor points the limitations would only apply in one direction.  And it does leave the question of how trains were worked or were the Regulations modified in the 'box Instructions?

[Eggesford box]

Hi,

 

going off at a slight tangent but have you gone onto the Modratec website at any time? There is a free downloadable program for interlocking a layout. It is obviously intended to be used with their interlocking kits (you produce your layout, press the button and it works out the interlocking and you send them the program and they produce a kit for the interlocking and frame though it may be possible to use their interlocking with another frame). I do not think it covers every possible permutation, maybe just me but I could not get it to lock a crossing by the next signal back when the signal 'protecting' the crossing is really tight to the crossing (a la Eggesford), but it is easy to use and quite pleasent to play around with.  

[Pannier Tank]

going off at a slight tangent 

and continuing with this theme!!; TRAX3 is also worth a look; it contains a CD with Software to write and check Signal Interlocking.

[LNERGE]

The interesting question about North Walsham is when the locking dates from

The line to Wroxham was singled in 1966. The Branch to Mundesley was removed in 1965. I imagine a fair bit of work was done around then.

[islandbridgejct]

I'm a little slow to expose myself to ridicule on this thread, but I'm fairly sure I read in an IRRS Journal a few years ago about the signalling at one of the stations on the Dublin - Rosslare line, that the home signal could only be cleared if the route was set at both ends of the loop - in spite of the fact that the far end of the loop was already protected by a starter. It seemed like a belt and braces approach but one that would send any train that failed to stop straight onto the mainline for a head on collision with a train held at the other home signal, rather than trap it in the headshunt.

 

This may have been standard practice at one time, having regard to comments on more modern practice in the UK above. It may have been an Irish thing. It may have been an Irish thing that could have happened in  remoter parts of Scotland too. Or I may have misunderstood the original article. The safety logic seemed flawed, but if correct, both 2 and 14 would be released by 4/5 and 11/12.

 

Alan

[RailWest]

There is no doubt that practices varied, both over time, and between different railway companies.

 

I know of two heritage railway locations where, in order to clear the home for entry into a loop, the route has to be set at the far end and that includes closing the facing traps. So...in the event of an over-run there may indeed be a head-on collision with an oncoming train waiting at the other home, but......that is deemed 'better' than the alternative in each case :-)

 

The only real answer - if there is one - in such cases is to try, as far as one is able, to determine the practice that would have existed for your chosen model's originating railway company at the time when the signalling was originally interlocked and also consider what changes in practice might have been included in subsequent modifications.

[The Stationmaster]

There is no doubt that practices varied, both over time, and between different railway companies.

 

I know of two heritage railway locations where, in order to clear the home for entry into a loop, the route has to be set at the far end and that includes closing the facing traps. So...in the event of an over-run there may indeed be a head-on collision with an oncoming train waiting at the other home, but......that is deemed 'better' than the alternative in each case :-)

 

The only real answer - if there is one - in such cases is to try, as far as one is able, to determine the practice that would have existed for your chosen model's originating railway company at the time when the signalling was originally interlocked and also consider what changes in practice might have been included in subsequent modifications.

It's interesting how the view on traps has changed over comparatively recent years let alone going back a century and more.  By the mid 1980s - following a number of derailments - HMRI were preaching strongly the removal of traps on passenger loops in order to avoid derailments.  In facts statistics were very strongly on the side of that conclusion as a succession of derailments following SPADs were down entirely to the presence of trap points whereas in fact none of those SPADs would have led to a collision or, probably, derailment if there had been no trap points.  So lots of schemes going forward from then on did away with traps on passenger loops.

 

Incidentally traps at single line crossing loops were only required 'in special circumstances' although one advantage of providing them - as instanced on the West Somerset line - has been explained above.

[Portchullin Tatty]

From what I can gather the Midland Railway was an example as they painted their point levers Oxford Blue. 

 

 Seems logical, as most if not all Midland Rly Facing Points were fitted with Economical locks, Prince's pattern I believe.

 Whilst on the subject of lever colours, the North British Rly painted its Distant Levers red, unlike other companus who painted them Green. Mick.

 

 

This from Jim Summers on the topic of lever colours:

 

Maybe I can still usefully point out that so did pretty well everyone else in pre-grouping days (and I believe Ireland continued to do so until power signalling).

 

Distant signals themselves were red, of course, but the green on the lever goes back to the days of time interval and handsignalling. White meant clear, green meant caution because the full time had not elapsed, and red meant stop and stay.

 

[Portchullin Tatty]

Hi,

 

going off at a slight tangent but have you gone onto the Modratec website at any time? There

 

Yes I was aware of this (and thanks also to Pannier Tank for a similar link).  I just have not played with it!

 

I will be for the next one; it will save my head from exploding with trying to work out the locking!

[John M]

I'm a little slow to expose myself to ridicule on this thread, but I'm fairly sure I read in an IRRS Journal a few years ago about the signalling at one of the stations on the Dublin - Rosslare line, that the home signal could only be cleared if the route was set at both ends of the loop - in spite of the fact that the far end of the loop was already protected by a starter. It seemed like a belt and braces approach but one that would send any train that failed to stop straight onto the mainline for a head on collision with a train held at the other home signal, rather than trap it in the headshunt.

 

This may have been standard practice at one time, having regard to comments on more modern practice in the UK above. It may have been an Irish thing. It may have been an Irish thing that could have happened in remoter parts of Scotland too. Or I may have misunderstood the original article. The safety logic seemed flawed, but if correct, both 2 and 14 would be released by 4/5 and 11/12.

 

Alan

 

 

Most single line crossings stations/places on the CIE system were set up to allow bi-directional running along the main line and loop, access to a loop was normally controlled by a calling on arm or "Loop Home" bracketed from the home signal.

 

Traps on running lines used by passenger trains are frowned on, however in some cases the loops extended through a crossover into headshunts or layby sidings for goods trains with the passenger line protected by traps.

 

Following a head on collision between two passenger trains at Rosslare Strand in the early 1970s (where shades of Cowden one train over ran the home and starter signals following a signalling alteration) home signals were moved out at many stations to provide increased overlap.

[beast66606]

This from Jim Summers on the topic of lever colours:

 

Maybe I can still usefully point out that so did pretty well everyone else in pre-grouping days (and I believe Ireland continued to do so until power signalling).

 

Distant signals themselves were red, of course, but the green on the lever goes back to the days of time interval and handsignalling. White meant clear, green meant caution because the full time had not elapsed, and red meant stop and stay.

 

 

Red is stop and green is go

But only white is all right.

[Portchullin Tatty]

The saga continues and I have now made all the trays and the bars that the locks go into.  As I have yet to colour the actual levers on the frame, I have coloured these to ease my understanding of things. 

 

As this is an experiment, I am making this out of plasticard/evergreen strip to speed construction.  The final thing will be in soldered and milled brass.  I have yet to come up with a plate to secure all these bars in place, so they will not flop out as they presently appear that they might.  This is what we currently look like:

 

 

 

I have been warned that I may snap my tappets from the locking bars or something else.  This is due to the significant mechanical advantage that the lever has over the through of the bar - if you look at the end view you can see that it is about 10:1, so I can see why I am being warned.  Ultimately this is an experiment so I will take it easy with the frame if it breaks I will know that it will need to be tougher next time!

 

[Portchullin Tatty]

No, this is not the end. It is not even the beginning of the end. But it is, perhaps, the end of the beginning. Interlocked Lever Frame – Part 4.  With thanks to someone else for the quote.

 

I managed to get all of the locking bars, installed over the weekend and the dogs (the teeth that engage in the sliding bars) to get the interlocking going. And this is what I get to:

 

 

This shows all of the components assembled in place. The dogs engage in slots in the sliding bars but the dogs have angled sides – so if nothing holds them in place the movement of the slider pushes them to one side and the slider can move. When another slider is in the way (ie there is an opposing lock set) then this can not occur – so it locks shut.

 

 

To stop the sliders popping up when they encounter a lock, a lid has been fashioned. I wanted all of the locking to remain visible, so this is just a skeleton.

 

 

I did find that the angles of the slots needed to be just over 45 degrees for the locking bar to move easily and they also need to match the dogs quite neatly. If I do this for real, I think some lost wax masters and then castings will be required to ease the process of manufacture.

 

The frame does lock well and neatly. Of course I made a few errors in where slots were to go but having made it from plastic, these were actually quite easy to sort out. What is more significant is that there is some slop in the levers – this occurs worst where the yoke of the bar that runs through to operate the toggle switch and sliding bars goes over the base of the lever. The hole in this is a bit too big and it means that the lever can move 30 % of its intended movement before it makes the sliding bar move and hence encounter the lock. This does slightly defeat the object of the locking and will need some work.  I have an idea of linking the two more physically but if this does not work, then it may be back to the drawing board.

 

All in all, it works though and it is quite fun working through the desired move, working out what then needs to be thrown and in what order – although this may send my team a bit over the edge in the heat of an exhibition! However, some manufacturing refinement is going to be needed to make it work better. I remain tempted to use the potential kit that might be available but this makes the locking invisible and I am not so certain about this. Food for thought!

 

 

[oscarcat]

The saga continues and I have now made all the trays and the bars that the locks go into.  As I have yet to colour the actual levers on the frame, I have coloured these to ease my understanding of things. 

 

As this is an experiment, I am making this out of plasticard/evergreen strip to speed construction.  The final thing will be in soldered and milled brass.  I have yet to come up with a plate to secure all these bars in place, so they will not flop out as they presently appear that they might.  This is what we currently look like:

 

_DSC10269compress.JPG

 

_DSC10271compress.JPG

 

I have been warned that I may snap my tappets from the locking bars or something else.  This is due to the significant mechanical advantage that the lever has over the through of the bar - if you look at the end view you can see that it is about 10:1, so I can see why I am being warned.  Ultimately this is an experiment so I will take it easy with the frame if it breaks I will know that it will need to be tougher next time!

 

_DSC10268compress.JPG

Can you tell me who makes these levers and the frame?

 

John

[Portchullin Tatty]

Hi John,

 

The lever frame is supplied by the Scalefour Society and is available to the public via their eshop here - you want item LFH and LF5 as the handles are a separate item.  The kit costs £20 and the handles 85p each.  There are cheaper prices for members in the main membership stores list - all you need to do is join the society to be able to get these!

 

The locking bars, tappets etc is of my own concoction.  I used plastic to prove the idea; if (or probably when) I do it for real I will be using something much more durable - probably steel.

[micknich2003]

A part view of a 16 lever frame I made some years ago.The are five bars in each locking box, two bottom and three top.

[Gordon A]

I dont think we have ever snapped any of the brass tappets on Tim V's (Clutton) lever frame.

 

Gordon A

[micknich2003]

 May be of interest.

[Portchullin Tatty]

I promised a number of people that I would be making sure that the layour had at least the main elements wired up over christmas, so that it could at last run.  But then it was a bit wet and cold so I did not fancy it out in the summerhouse so I applied rule no 1 – its my trainset!

 

Instead, I stayed at the bench and made a pair of the signals that still remain to be made for Glenmutchkin. The signalling plan has developed very slightly since I originally and is shown below (actually this is the artwork for the control panel facia).

 

 

The signals that I built were those that control the main loop prior to the shed link – levelrs 27 & 28 – and then the outer starter (that covers both the main loop and the main line) – levers 23, 24, 25 & 26.   Only a pair of two doll signals, I thought, they shouldn’t take more than a day or two?  Phew, well that wasn’t right; the more you look at the prototypes, the more you find there is to model!

 

Having created much of my own etchings and castings for MacKenzie & Holland signals I have obviously made good use of these.  In this case, the small brackets, arms, ladders and castings.

 

 

Both of the signals have used the small brackets to create smallish landings.  The smaller of the two signals has only one arm per doll, the larger two.  The dolls and the posts are made up of square brass section which is filed to a taper – a certain amount of elbow grease is needed to acheive this!  The posts are then sandwiched between some transom beams that also clasp the doll post – this is all soldered with a high melt solder to stop it ungumming later.

 

 

The brackets are then offered up from below, with scrap etch forming the bearing plates to pick up the transomes.  In the etch I also included smaller brackets to pick up the free end of the landing, along with the landing itself.  This gets you to the stage shown above.

 

But this is not the half of it on a signal, there are the finials, lamp brackets, lamps, cross stays, access steps, access ladders, pivot plates, handrails, operating cams, safety hoops and ladder still to do………..

 

 

In a departure from my previous practise, I made the main ladders detachable (they will be held with the wire that can be seen in the pictures being turned over in secret pockets.  I am also going to paint this prior to the final assembly; which will mean some touching uo of the painting later but I hope will make it easier.

 

 

And of course, I had to sign them with these rather nice custom name plaques from NBR 4mm Developments.

 

 

This is the first time that I have used the brackets in signal making and I was pretty chuffed with how they have come out.  This is where things presently stand and we head for the paint shops tomorrow…….