Masokits etched chairs turnout construction for Kyle of Lochalsh

Discuss the prototype and how to model it.
ted.stephens
Posts: 13
Joined: Fri Nov 30, 2012 6:04 pm

Re: Masokits etched chairs turnout construction for Kyle of Lochalsh

Postby ted.stephens » Mon Apr 05, 2021 8:29 am

Here is an extract from SR Pway Drawing No 12 showing the E switch arrangement.

E Switch Plan.JPG


The positions of the joints as noted from Templot are the same as those shown on this drawing, red circles. You are correct in that there isn't enough space to fit separate chairs at the joint, this area of the switch is supported by PR and PL chairs, Nos 1 to 9.

On this drawing the L1 chairs appear on the 20th bearer from the switch tip.

Julian Roberts
Posts: 1016
Joined: Sat Jan 09, 2010 11:33 pm

Re: Masokits etched chairs turnout construction for Kyle of Lochalsh

Postby Julian Roberts » Mon Apr 05, 2021 8:35 pm

Hello Ted

I'm very grateful for your assistance. I didn't really expect anyone to come up with an answer to my question, or even that anyone would be reading it!

It's a relief that I've cut up the rails to the right lengths.

My main issue now, having been enlightened by your post, is where to first fix the switch (how far from the tip) as I think I read on Tony's turnout thread that the last two of what look like slidechairs are block chairs that allow some movement (on a B switch) - which leaves me a bit muddled but I haven't got round to asking in the right place. If that is the case here it might seem the rail isn't fixed till after the joint. But - where the prototype fixes it isn't necessarily where I will fix it as (I think) the model rail is relatively stiffer. But to know how the prototype does it is the first stage. I have a real joint but soldered together firmly with Masokits fishplates using higher temperature solder.

ted.stephens
Posts: 13
Joined: Fri Nov 30, 2012 6:04 pm

Re: Masokits etched chairs turnout construction for Kyle of Lochalsh

Postby ted.stephens » Tue Apr 06, 2021 7:46 am

Here is the detail around the area of interest. The bearers are numbered from the switch tip.

Capture1.JPG

In all cases the stock rail is bolted to the PJ chairs with a bolt passing through the web of the rail and a nut on the outside. No cast iron blocks are required up to and including bearer 7 because the point rail is planed up to this point and is supported laterally by resting on the stock rail face so can't move outwards.

Bearer 8 PJ chairs are shown as only having a stud bolt.

The PJ chairs on bearers 9 and 10 have cast iron blocks to support the point rail laterally and to stop any outward movement whilst allowing the point rail to move inwards when that side of the switch is open. The bolt fixes the cast iron block to the stock rail.

Capture2.JPG
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E switch chairs, from bearer 11 onward there are 9 PL/R chairs which fix both stock and point rails. Note the position of the switch anchor is shown between bearers 11 and 12.

Capture3.JPG
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A to D switch chairs 1PL/R and 2PL/R allow the point rail to move inwards which explains the apparent anomaly.

Capture4.JPG
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Tony Wilkins
Posts: 552
Joined: Tue Mar 20, 2012 3:57 pm

Re: Masokits etched chairs turnout construction for Kyle of Lochalsh

Postby Tony Wilkins » Tue Apr 06, 2021 12:06 pm

Julian Roberts wrote:Hello Ted

My main issue now, having been enlightened by your post, is where to first fix the switch (how far from the tip) as I think I read on Tony's turnout thread that the last two of what look like slidechairs are block chairs that allow some movement (on a B switch).


Hi Julian.
Ted's post has clarified the situation regarding E switches accompanied by a wonderful set of drawings.
Your comment above is correct in so far as it goes, but the combination of slide and block chairs is a little more complicated than that.
For most types of switch there are a number of P slide chairs followed by a number of Block chairs. So far so good.
For A, B, C and D switches the first two block chairs of each switch allow the blade to move.
For A, B and D switches, the remaining block chairs firmly hold the rail in place. D switches have four fixed block chairs, two of them beyond the joint.
C switches have three fixed block chairs before the joint.
The situation with E and F switches is different as they only have P slide chairs and fixed block chairs, the first two of which before the joint are fixed (as Ted's drawing shows), and had the keys on the inside of the rails, as there was not room for them in the usual place.
So a sprung switchrail will always be held fixed by at least two chairs before the joint.

Incidentally only the LMS and SR used REA F switches. The largest the LNER used were E switches.
Regards
Tony.
Inspiration from the past. Dreams for the future.

Julian Roberts
Posts: 1016
Joined: Sat Jan 09, 2010 11:33 pm

Re: Masokits etched chairs turnout construction for Kyle of Lochalsh

Postby Julian Roberts » Wed Apr 07, 2021 4:58 pm

Hi Ted and Tony

Many thanks both for all this help. Would it agreeable to you if I copy and paste that exchange onto the turnout question thread?

I've got a limited choice remaining in etched chairs.  There are running chairs, slide chairs, and block chairs to choose from for this area.  The block chairs have no key so I've used a running chair outside the stock rail - which has only one bolt....(Check rail chairs have two bolts but I've used them all up) 

20210407_164605.jpg


The block chairs are limited in quantity - half of them have two bolts and half of them one as here.

The two inside chairs to the right of the fishplate (towards the blade tip) inside are truncated slide chairs. Does this look right(ish) I wonder.

20210407_174059.jpg


Or is this right (ignoring foreground stockrail chairs)

20210407_164637.jpg


I think this one is right re- reading the previous post. And more block chairs to the left of the fishplate of course

Tony Wilkins
Posts: 552
Joined: Tue Mar 20, 2012 3:57 pm

Re: Masokits etched chairs turnout construction for Kyle of Lochalsh

Postby Tony Wilkins » Fri Apr 09, 2021 3:10 pm

Julian Roberts wrote:Hi Ted and Tony

Many thanks both for all this help. Would it agreeable to you if I copy and paste that exchange onto the turnout question thread?

Hi Julian.
I certainly have no objection.
Regards
Tony.
Inspiration from the past. Dreams for the future.

Julian Roberts
Posts: 1016
Joined: Sat Jan 09, 2010 11:33 pm

Re: Masokits etched chairs turnout construction for Kyle of Lochalsh

Postby Julian Roberts » Mon Apr 12, 2021 11:42 am

I bought blades primarily so that I would know the stockrail side would be mating properly with the stockrail, flush all the way, once it is straightened.

So the tip of the diverging blade is 0.15ish or less - pretty damn fine for a joggled switch. It's 1.9 high or maybe a tad over, 1.95. The Web on the stockrail side is not apparent till 20mm from the tip.

With the stockrails set up without joggles, the tip fits at about the second timber.

20210408_121159.jpg
Nice tip as it comes


20210408_115801.jpg
But too wide without joggles


Now I'm going to wreck it to make it undercut. 8-)

This is the table I made for a B blade. The E blade is double the length.

Table of width and height undercut blade.jpg


It took me about 3 hours on each blade to get them undercut to what I think should work. I'm a slow worker. It worked nicely with a couple of compensated test vehicles just held in place with two nails. It seems to me (from my limited experience so far) the critical bit is where the blade rises to the gauge height, which is around 12mm from the tip here.

20210409_124107.jpg


The stockrail gauging had been all re-done, reverting back to no widening. Here it is at the stockgauge with the actual switchrail being used.

20210411_213153.jpg
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Now I'm going to try out Martin's approach, despite Tony and Keith suggesting otherwise, and spring the blade against the stock rail. The rail has to be bent slightly and held with the block chairs. I'm starting with the diverging blade. The turnout is a LH, on a right hand bend.

Without stretcher bars the blade opening is more than spec with a flangeway gauge tool at the stockgauge position.

20210411_205748.jpg
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The spring is quite enough with the blade fixed 5 timbers further from the tip. This amount more flex will I hope help the issue of the blade opening once stretcher bars do their stuff. The remaining block chairs towards the tip will be cosmetic, fixed to the blade only.



The stockrail is now fixed properly (slide chairs and block chairs downstream from the stockgauge now properly guaged) making sure I don't disturb the switch rail when using the tool.

20210411_220508.jpg


I've managed to fit in the bridge chairs at the 20th bearer, with a bit of persuasion.

20210411_220527.jpg


(I should have specified or asked if I could have the blade the length I needed. As it came it was as long as anyone would normally need, but I had arbitrarily drawn up on Templot a 60 foot length after the switch rail joint. The turnout will thus have a real rail break to allow for expansion etc, possibly unnecessary, where the real one might have had (no photos to that amount of detail of this location in the cutting). Templot doesn't show any break on this length turnout between those at the blade and the crossing as it was variable between companies or according to circumstances (if I understand correctly).

Anyway I cut the bought blade at the rail break between S12 and 13 and attached longer rails, using Masokits fishplates which act as railjoiners too.)

Julian Roberts
Posts: 1016
Joined: Sat Jan 09, 2010 11:33 pm

Re: Masokits etched chairs turnout construction for Kyle of Lochalsh

Postby Julian Roberts » Sun Apr 25, 2021 8:11 pm

Switch now set up with three stretcher bars. Working perfectly testing with some large wheel locos (CR 4-4-0 and 0-4-4 - the Compound completion has been pushed into the long grass again, like the Williams review of rail franchising). Just a lot of chairs to do now. The crossing end was complete some time ago bar some chairing details.

Rather fuzzy video shows actuation will have to act midway so as to pull on both ends. Actuation will be below the baseboard in a yet to be finalized manner- these piano wires will be bent downwards through the board. I didn't find the blade set up is rigid enough for one ended operation. I'm not sure if the springing of the blades served a useful purpose, except that testing was possible and successful without stretcher bars, with a drill bit holding one blade open.




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