Masokits etched chairs turnout construction for Kyle of Lochalsh

[Julian Roberts]

6 wheel parcels van, no problems on this curved slip.



3 wagons propel Crab loco and tender (gearbox disconnected) which weighs a good 7 or 800g. My hand causes the only derailment near the end, steering the wagon the wrong road. Edit - The curve is such that only 2 buffers are in contact between each propelled vehicle




In spite of warnings that propelled small wheeled goods vehicles are the problem, testing has shown no wagon problems, and only one derailment, on my one loco that has a slightly overgauge front wheelset.



I've tested every loco in each direction with the driving wheels in four different positions, starting on the central timber. On the Class 782 In just one driving wheel position the derailment happens, at one place. This loco has, for a shunting engine, a long wheelbase, but plenty of sideplay is built in. However the front wheels are overgauge, up to about 17.82 at their widest point. Edit - rather horrified that I didn't notice the front step has broken. I spent hours on that!



However, this has been cured to the extent that the loco now makes a discernible clunk (turn the volume up to max) but does not derail, by adjusting the checkrails to a narrower flangeway gap. I don't have an S4 gauge (0.58), but the back of a Stanley knife blade is 0.60. A sharp bend of the checkrail as Dave B recommended (I see Tony Wilkins suggests the same) caused a perceptible lurch at this narrower setting, but bent over a say 4mm drill shank this arrangement seems to work OK for all the stock, with no downside. This is despite quite a few of my loco wheels being under the recommended 17.67 narrowest BB setting. They are not adjustable as I used Araldite when putting them together, and it is simply by accident they are set too narrow, as is the case with the 782 being too wide.

I was expecting these inadvertantly narrow wheelsets to have problems on this diamond, but this has not been the case, even with the adjusted checkrails. Even my narrowest wheelset, at one point in the revolution being 17.47, shows no issue.

The narrower setting for the checkrails makes the wagons harder to steer the wrong way by hand, though it is still possible.


During a week of testing I found, thanks to Martin's help, that the single slip is a regular 1:8 straight. https://85a.co.uk/forum/view_topic.php? ... 526#p31526

So now I'm in a dilemma. The crossing works fine - but will it with larger locos I hope to make, including a WD 2-10-0? Will the angle of incidence become a problem where it has not so far? A 1 in 8 straight crossing will not have any such problem - but means starting again, as well as needing to be designed to fit in with the neighbouring turnout which is already constructed.

A dummy vehicle, compensated of course, has been made to the WD wheelbase, plus about 3 mm to approximate the length over flanges with bigger wheels, and shows no desire to go the wrong way, but can be persuaded to, rather more easily than the short wagons.

More exciting videos of the Crab on the diamond at https://www.youtube.com/channel/UCgA4F5 ... subscriber

[Tony Wilkins]

Point rails for obtuse crossings should never get that thin. 0.1mm or 4 thou is thin enough for me rather than the normal 0.25mm. Martin. Thanks for republishing this information. I have taken the liberty of copying the data into my track construction thread (with acknowledgements) so it is available there too.

Hi Tony,

Normal for REA bullhead blunt point rails is 1/2" nose = 0.17mm , rather than the 3/4" (0.25mm) for blunt vee nose. (GWR is 11/16" for both.)

You are welcome to the info -- it's actually in the K-crossing help notes in Templot, and has been there for about 20 years.

cheers,

Martin.

This reply is a bit out of sequence now, but I would just like to clarify that I don't normally use a 0.1mm thin / thickness point rail nose but in exceptional circumstances where one is fighting the odds then I will do so.

My 1956 copy of the P way handbook states that for bullhead rail the blunt nose of an obtuse point rail 3/4" wide same as for the vee nose, but notes that It was the practice of some railways to plane the point rails of 6 1/2, 7, 7 1/2 and 8 obtuse crossings to a nose of 1/2". So you pays your money and takes your choice.
For Flat bottom rail it is stated as 1/2 " 'to reduce as much as possible the long gap which exists between the two point rails of an obtuse crossing.' (Page 106) Common crossing noses are 5/8" for flat bottom rather 3/4" for Bullhead. Flat bottom P&C is a whole new ball game.

Regards
Tony.

[Julian Roberts]

Although the irregular curved single slip basic diamond works perfectly for all my stock I reluctantly decided to redesign it as a regular straight slip. The other discussions that led me towards this point are here - https://85a.co.uk/forum/view_topic.php? ... 658#p31658 and here
viewtopic.php?f=5&t=5728&start=150

I hope to make sometime a WD 2-10 -0 and other large engines, and don't want to be limited by this potentially troublesome piece of track.

Apart from the festivities, the time since the last post has been spent in trying to think up a cheaty way of modifying the slip and that retained the offstage turnout already built. However I've failed and the only thing for it is a newly designed diamond and offstage turnout, screenshot below. I may be able to adjust the physical existing diamond rather than start afresh; and the offstage turnout will I realise be completely invisible, so not require any chairs. Half of the existing one - the switch half - can be used as it is. The offstage turnout is a couple of inches shorter too, so the layout length (before fiddleyards are added) is thereby usefully reduced.

The previous turnout ended at the 96 inches vertical line

[Julian Roberts]

Diamond Round 2. Straight this time.

I've got the benefit of Tony Wilkins' description of how to do it this time. Which presented me with a dilemma pretty well at step 1 after making the Vs. He says make the two stock rails knuckles opposite each other at the centre of the diamond to start with, while last time round I made one, made two point rails and then gauged the other knuckle off that. As mine had worked very well, and as I couldn't see how to gauge the two knuckles off each other apart from at the very centre, I thought I'd do it the same way as last time. The rail joints are all near the centre, following the Exactoscale drawing.

On the slip road at the switch there isn't room for a rail joint unless it's going to be right by either the knuckle or switch. So I'm just doing the very centre to start with, and this has the advantage the point rails don't have to fit into an absolutely exact prescribed length.

The Templot template came out with a very few timber lengths that didn't look symmetrical between one half of the diamond and the other (I must have done something weird but it looks fine otherwise), but I haven't got all the timber lengths looking right.

Day one - two Vs, and the first knuckle. This time I have no jig to make the Vs which are approx a I in 7.8 angle, so it took time to find a way that worked for me, but it's really very easy. A long ruler confirmed the knuckle lines up with both Vs.

A slight adjustment was needed to ensure it was in line at one end

Day 2 (Jan 1st - Happy New Year anyone reading this!): adding two point rails using the ruler from the V to the knuckle and flangeway gauge. The first point rail may be placed a bit short, exaggerated in the photos, and the second placed a bit long - relative to the blunt tip mark.

2nd point rail

Now the opposite knuckle can be added. This is tricky and I wouldn't like to imagine doing this using glue as it needs constant readjustment till it's right (it would be easy if it were two separate rails). The block gauge has to be snug both ways.

This second stock rail is at the same time checked that it lines up in both directions - this is one of them.

However at the very centre, having got it all to what seems right, the gauge is 0.1 wide, and I can't understand how that can not be a tad wide depending on the radius of the curve of the knuckle on the stock rail. They were bent over a 10mm drill.

Then the timbers that go under the point rails were added, and a whole lot more readjustment was needed to make sure that the block gauges were not too tight yet not loose at all in each direction. It involved moving leftwards the point rail that was placed too long. That was day 2.

After all that it would be relatively easy installing the other point rails, except they're trickier to actually hold. The scriber pen has a magnetic top which is useful for holding the flangeway gauge.

As appropriate, where the rails are supported on 0.5mm shim the inside running chairs will be used cosmetically. The etches don't provide enough block chairs I think; inside running chairs look very similar but don't function in raising the rail.

[grovenor-2685]

However at the very centre, having got it all to what seems right, the gauge is 0.1 wide, and I can't understand how that can not be a tad wide depending on the radius of the curve of the knuckle on the stock rail. They were bent over a 10mm drill.

20201231_184526.jpg

You can't measure gauge across the two knuckles like in the picture, firstly you are not measuring at 90 degrees to the track centreline and second as you mention the knuckle radius also affects it. Just measure gauge from the end of each point rail to the opposite rail at 90 degrees, ie one timber away from the centre, what happens between these positions, ie at the centre timber is just what it is, you would need a specially made gauge to test it and it would serve no useful purpose anyway.

[Will L]

I'm with Keith, don't think that particular 0.1mm will matter. I have to say I do like the way you persist with problems till your happy with the result. In my book thats the mark of the successful modeller. Keep at it.

[Jeremy Suter]

I agree with Keith. You are not actually measuring the gauge in that picture merely the distance between the two rails it should be wider that way the gauge needs to be perpendicular to the running rails

[Julian Roberts]

Thanks chaps for correcting me. I wonder how many other things I don't understand. I had another look at the photo on Tony's thread and I see that it is like this, which I think is what you are saying is how I should measure it.

However, I do understand that the distance as I measured it doesn't matter. Anyway the proof is in the eating, rails lashed up now to test, and a wagon sails through, propelled by another one, so on with the job of the rest of the slip.

And thanks for the encouragement Will! I was most impressed at how you saved the Buckjumper injector detailing. Earlier on I showed my 782 loco and later I was horrified to see that the front step has broken in half. It took me hours getting that looking right, yet I didn't even notice, I don't know how long it has been broken. Sometime I'll find the rountuit to get it mended.

[grovenor-2685]

IIRC Tony said he was just using the gauge in that position for temporary support, it can't function as a gauge in that position for the reasons we already mentioned. You must have a point rail in place to measure the gauge.
Anyway it looks like yours is coming along fine.

[Terry Bendall]

I wonder how many other things I don't understand.

It might be quite a lot Julian but in reality probably not a lot.

Anyway the proof is in the eating

That tends to be my approach. If it works - fine, move onto the next thing. If it doesn't try and sort it out and seek help if needed. I once had a wagon which kept de-railing. I did all the checks - back to back, wobble, concentricity, track gauge to no avail. Then I notices a small lump of glue on a tread that I had missed. No idea how it got there but remove it and problem solved!

I think it called sticking with a problem and having the patience to solve it.

Terry Bendall

[Philip Hall]

If it’s glue on a wheel tread it truly is sticking...

Philip

[Julian Roberts]

I wonder how many other things I don't understand.

It might be quite a lot Julian but in reality probably not a lot.

Well I keep thinking I know things, after all my irritating questions on the Forum I've really learned such a lot from you folks, all of it freely and generously given - and then realise there are still unknown unknowns, plenty of them. Some folks have got annoyed at some of my questions and have said it may put people off P4, but I think it's better to have that sort of conversation than the nightmare correspondence that has been going on just now on a couple of other threads.

Yes re the bit of glue, and my tendency is to catastrophize and think something fundamental is wrong in such a situation, so it's really worth bearing what you say in mind before going in with the soldering iron or worse.

This morning I'm wondering how this slide chair that will support the switch tips fits or rather perhaps the question is how the rail I've already put there is supported. The bolted half chair will support the rail, but the slide chair will have to have the end truncated a bit. Perhaps there are in reality shorter slide chairs. Cosmetic problem entirely of course.

[grovenor-2685]

There looks to be slightly more of an issue there than just the slide chair. The switch tips need to be to the left of the insulated joints so either your slide chair needs to move left one timber, or the insulated joint needs to move right one timber and if the latter the timber spacing needs adjusting as the joint should be in the narrow bed.
And, yes the slide chair needs shortening so it doesn't cause a short. It's more of a problem with double slips.

[Julian Roberts]

Thanks Keith.

The insulation is done with rail joints towards the centre of the assembly as seen in the picture, following the Exactoscale drawing for a 1 in 8. I haven't got any plastic fishplates yet. Some fussy gapping has to be made before the next rail is fixed here - while most of the gapping has yet to be done.

It might have been better to make the stock rail at the top in this picture one piece over the whole assembly. I've had some trouble with getting the rail levels even at the joints. As it is only the slip road stock rail nearest the camera is the only continuous one. Though I'm not sure yet about wiring this up electrically in the context of the whole layout, it may prove that joints are needed.

I've found that raising the check rails about 0.5mm makes them effective at this 1 in 7.8 angle and prevents wagons taking the wrong route, not that they particularly want to. The check rail height isn't noticeable by and large I think.

Still quite a lot of chairing detail to be done between rails and elsewhere, and one more blade. I find that inside bridge chairs don't fit where the drawing says they should in some locations - the cheat of using "fillers" will hardly be any different, at my level of technique at least.