Turnout construction - Question here please.

Discuss the prototype and how to model it.
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Martin Wynne
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Re: Turnout construction - Question here please.

Postby Martin Wynne » Sun Oct 20, 2019 8:27 am

Julian Roberts wrote:Shame Tim's film doesn't show this part of the process!

Hi Julian,

It does show knuckle bends being made, at around 6 minutes 30 seconds in.

Here is another old film about junction renewal:



cheers,

Martin.
40 years developing Templot. And counting ...

Julian Roberts
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Re: Turnout construction - Question here please.

Postby Julian Roberts » Sun Oct 20, 2019 2:47 pm

+1 ......not least, for the great music sound track!

TEZBEDZ
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Re: Turnout construction - Question here please.

Postby TEZBEDZ » Thu Apr 16, 2020 11:23 am

I built 11 turnouts on my layout Llanfyllin, but, 1 is giving me a lot of grief.
One turnout refuses to work properly. I dont know the correct terms but when used as a trailing point all vehicles pass through correctly without detailing.
When vehicles go through as a facing point all weighted wagons go straight on, none will turn. However I have a plastic box van without weight which turns.
The switch blade fits flush up against the straight rail and the wagons dont derail. I have checked their back to back and also the gauge through the turnout
Any ideas why?
Regards

Terry

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Will L
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Re: Turnout construction - Question here please.

Postby Will L » Thu Apr 16, 2020 11:36 am

Are your wagons rigid, compensated or sprung. If a mix does the type of suspension make any difference?

The next step is to get your eyes down to tack level and watch what happens as the wheels go through the point.

Winander
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Re: Turnout construction - Question here please.

Postby Winander » Thu Apr 16, 2020 12:27 pm

I have looked in the digests and the turnout construction thread accompanying this questions thread and cannot find the answer to the following:

What distance apart do I fix the switch blades when fixing the stretcher? Or phrased another way, how much gap do I leave between the outside of the switch blade and the stock rail? I assume the check gauge comes into play, but suspect a little more is allowed on the model (which means the prototype dimension is not useful).

Thanks in anticipation....
Richard Hodgson

Winander
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Re: Turnout construction - Question here please.

Postby Winander » Thu Apr 16, 2020 12:32 pm

Will L wrote:Are your wagons rigid, compensated or sprung. If a mix does the type of suspension make any difference?


Also test your wagons by rolling them down a glass (or as flat a thing as you can get) incline. If they don't roll straight, the axles are not parallel.

As Will says, we need some more details of the wagons used such as wheelbase and weight.
Richard Hodgson

davebradwell
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Re: Turnout construction - Question here please.

Postby davebradwell » Thu Apr 16, 2020 1:30 pm

Winnander - Blades on the prototype open to give a 4 1/4" gap to the stock rail - it's far more than the check gap and scales at 1.4mm. A drill shank makes a good gauge. If the rails are joggled, the opening should be measured to the bit that is to gauge ie away from the joggle. It is a very common error to provide inadequate opening and can result in a wheel catching the end of the "not open enough" blade. This dimension is from an LNER turnout but is unlikely to vary between companies.

With troublesome pointwork, try holding a rigid wagon and just pushing it through very slowly. You can bias it towards the closed blade and feel for it catching the blade which must then be fettled until the wagon passes the end of the blade without a detectable step. There's been plenty on teh forum about blade end shapes.

DaveB

Winander
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Re: Turnout construction - Question here please.

Postby Winander » Thu Apr 16, 2020 1:51 pm

Thanks Dave, the tip to use a drill is also helpful.
Richard Hodgson

Tony Wilkins
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Re: Turnout construction - Question here please.

Postby Tony Wilkins » Thu Apr 16, 2020 2:27 pm

Certainly the nominal distance for the blade opening is usually quoted as 4 1/4" although I am sure I have seen 4 1/2" quoted in some instances.
4 1/4" or 1.4mm scale should be adequate for our purpose. I do sometimes use 1.5mm for P4 blades for luck.
However my feeling is that the fault is most likely due to the fit of the closed switch blade against the stock rail. P4 flanges being so fine can pick up on remarkably small projections from the true line. Run your finger along the running edge and see if you can feel any step or corner at the start of the switch blade as this should feel smooth.
Something else to look out for is the finish of the top of the switch blade. If this is flat at the very tip then it is possible for the flange to ride up and run along the head of the switch rail instead of being deflected sideways by the face of the flange.
Regards
Tony.

TEZBEDZ
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Re: Turnout construction - Question here please.

Postby TEZBEDZ » Fri Apr 17, 2020 8:18 am

Will L wrote:Are your wagons rigid, compensated or sprung. If a mix does the type of suspension make any difference?

The next step is to get your eyes down to tack level and watch what happens as the wheels go through the point.

Thanks. Looking at track level helped and I discovered that the gauge narrowed a tiny amount about 2mm before the joggle on the curved stock rail. This tiny amount was enough to lift the wheel above the switch rail.
Regards

Terry

Terry Bendall
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Re: Turnout construction - Question here please.

Postby Terry Bendall » Fri Apr 17, 2020 11:26 am

TEZBEDZ wrote:Thanks. Looking at track level helped and I discovered that the gauge narrowed a tiny amount about 2mm before the joggle on the curved stock rail


There is always a reason - the trick is finding what it is. :) The lack of weight would not have helped. When looking for faults I sometimes put a piece of lead or something of similar mass on top of the errant vehicle and see if it makes any difference. If everything else runs through the problem is usually with the vehicle.

Terry Bendall

bécasse
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Re: Turnout construction - Question here please.

Postby bécasse » Fri Apr 17, 2020 12:30 pm

Terry Bendall wrote:
There is always a reason - the trick is finding what it is................. If everything else runs through the problem is usually with the vehicle.


........ but not always.

I can go back some 49 years when we found at our first exhibition that some wagons (uncompensated in those days of course but well weighted) didn't like being propelled into the goods siding. We couldn't find anything wrong with wagons concerned and checks quickly showed that the point was spot on for gauge. It wasn't long before the tongues started to wag "we always said that this finescale stuff may look very nice but it clearly doesn't work".

It wasn't until one of our group, a pw engineer, found an old plan buried in the railway's archives that the mystery was solved - because written in pencil on that plan was a list of wagons, real 304,8mm to the foot ones, known to have derailed on the prototype point. Our track work was built to the precise plans of the real thing, fortuitously recorded by the same engineer before the track was lifted, and in doing so we had managed to replicate the point's faulty geometry - and derailments! The geometry of secondary track work, which used available secondhand materials, was often "bodged", usually without too many ill effects.

Winander
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Re: Turnout construction - Question here please.

Postby Winander » Fri Apr 24, 2020 9:29 am

Is the track gauge listed in the stores as "Track gauge, Type 'A', Brook Smith" the one in the picture below (stolen from Tony's construction thread)?
Q Book Smith Gauge.jpg
Q Book Smith Gauge.jpg (143.39 KiB) Viewed 847 times

Also, can anyone please supply photos of gauges TGS4/1 and TGS4/2 that Alan Gibson sells? Listed in the catalogue as follows:
TGS4 Set of four Scalefour track gauges
TGS4/1 Scalefour track gauge - actually holds running rails
TGS4/2 Scalefour Rolling gauge for checking for tight spots
TGS4/3 Scalefour Crossing flangway spacer
TGS4/4 Scalefour Check rail gauge
TGS4/5 Scalefour three point track gauge (not above set)

(From the blurb in the catalogue TGS4 is a set of four of the gauges listed after it.)

I am only interested in TGS4/1 Scalefour track gauge - actually holds running rails and TGS4/2 Scalefour Rolling gauge .

If TSG4/1 is not the 'traditional' three point gauge (TSG4/5) then what is it?

Thanks
Richard Hodgson

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stephenfreeman
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Re: Turnout construction - Question here please.

Postby stephenfreeman » Fri Apr 24, 2020 2:30 pm

I wasn't aware that Alan Gibson supplies the gauges, I bought mine from the stores. Assuming these are the same, you have posted a picture of the first gauge you are interested in. I'll try and post a photo of the other one but expect to be beaten to it.
Stephen Freeman
Bespoke Finescale Trackwork and Semaphore Signals 7mm to 4mm scales
https://www.tracknsignals.co.uk

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stephenfreeman
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Re: Turnout construction - Question here please.

Postby stephenfreeman » Fri Apr 24, 2020 2:42 pm

hope this helps
gauge.jpg
gauge.jpg (231.21 KiB) Viewed 778 times
Stephen Freeman
Bespoke Finescale Trackwork and Semaphore Signals 7mm to 4mm scales
https://www.tracknsignals.co.uk

Tony Wilkins
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Re: Turnout construction - Question here please.

Postby Tony Wilkins » Fri Apr 24, 2020 3:30 pm

Hi Richard.
Yes, the track gauge pictured is a Brook Smith track gauge and was part of a set then available.
It also contained one as pictured above.
I thought the picture looked familiar.
Regards
Tony.
Last edited by Tony Wilkins on Sat Apr 25, 2020 5:22 pm, edited 1 time in total.

CornCrake
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Re: Turnout construction - Question here please.

Postby CornCrake » Sat Apr 25, 2020 9:03 am

Picture of Brook Smith Type "A" received from stores last week:-
Brook_Smith_Type_A.jpg
Brook_Smith_Type_A.jpg (73.42 KiB) Viewed 656 times

Steve

Winander
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Re: Turnout construction - Question here please.

Postby Winander » Sat Apr 25, 2020 10:44 am

Thanks very much for all the responses.

I had reached the conclusion that the picture I posted when posing the question was the Brook Smith type A, but thanks to Steve, not the case!
Richard Hodgson

CornCrake
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Re: Turnout construction - Question here please.

Postby CornCrake » Sat Apr 25, 2020 11:17 am

Hi Richard,

Thought you might like to see the component parts:-
BS_Type_A_Components.jpg

The important part is the "bobbin" which looks very similar to the "bobbin" part depicted in the first photo that you posted from Tony's track building thread.

Steve

Winander
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Re: Turnout construction - Question here please.

Postby Winander » Sat Apr 25, 2020 11:28 am

Hi Steve,

Thanks for this, I had concluded that being described as Brook Smith, and from the look of it, it might grip the rails vertically and cause gauge problems if using plastic chair construction rather than rivets. It's documented elsewhere on the forum as a problem with some triangular gauges that have the 'legs' too long - when the rail is released they spring into the 1:20 inclination imposed by the chairs and result under gauge.

Your latest picture is really useful and I do see the similarity - thanks very much for taking the time to post it, it looks just what I need.

best wishes
Richard Hodgson

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stephenfreeman
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Re: Turnout construction - Question here please.

Postby stephenfreeman » Sun Apr 26, 2020 11:30 am

Ah! the ones based on the nut and bolt were, if memory serves me right the original Alan Gibson product from when he used to sell the range for Len Newman. To avoid any possibility of the gauge narrowing effect best to not have the nut adjusted too tightly. The current 3 point gauges available from the stores only sit on the head so should be OK. By turning up a suitable sleeve you can adapt the original gauges to suit other gauges to P4 standards. As well as having a Society 3 point gauge for IrishP4 this adds a couple of extra gauges when I need them.

I wasn't aware that the nut and bolt gauge was still available, so useful to know. In fact the design seems to have changed in that instead of the "bobbin" there used to be 2 shouldered washers and a spacer tube. The new design obviously doesn't lend itself to the Irish mod above.
Stephen Freeman
Bespoke Finescale Trackwork and Semaphore Signals 7mm to 4mm scales
https://www.tracknsignals.co.uk

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grovenor-2685
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Re: Turnout construction - Question here please.

Postby grovenor-2685 » Sun Apr 26, 2020 4:31 pm

The original bolt together guages were the Protofour Mk II, as illustrated here
https://www.scalefour.org/history/protofoursociety/manual/4.1.5-gauges
I have a set but still use the Mk 1 more often.
Regards
Keith
Grovenor Sidings


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