I very much enjoyed reading Trevor Hughes' account in NG&IRMR 123, of making track for his new Pendre layout. One query I have, which is totally down to my ignorance of the subtleties of narrow gauge track, concerns how the point blades are machined to fit against the stock rail. I have recently finished the track on a P4 light railway (standard gauge) using Code 60 flat bottom rail. My researches suggested that the foot of the stockrail was left intact and the outer foot of the point blade was machined at an angle to ride onto the foot which supported it. The inner foot of the switch being left intact. Prior to this project, and in my limited experience of 7mm NG flat bottom track making, using Karlgarin rail, I had filed away the foot of the stockrail as Trevor has done, to make a notch to accommodate the switch, although I later read that this was not 'prototypical' as it weakened the stockrail. However knowing Trevor will have gone to great pains to get the track correct, and studying the prototype photos in the article confirms that the stock rail did indeed have its foot cut away to make a seating for the toe of the switch blade.

Is there any hard and fast rule to this? or did it depend on the individual railway company's Chief Engineer?!

Steve

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Hi Steve
There doesn't seem to be any hard and fast rule. Whenever I see a railway or photos I'll always study the pointwork. It?seems to be on older or simpler railways both the blades and stock rails were planed with the main feature being the original rail feet are at the same level and some more modern lines have the blades planed so they fit on top of an unplaned stock rail foot as you suggest. This requires both long blades and very sophisticated planing of the sides and top of the blade rail, and sometimes special sections of rail. Have a look at Wenz Modelbau website for German examples of such blades.
I should add that planing both is probably easier - and the inner side of the blade should be planed first.
John

Thanks for those pointers Gents, I now see from John's articles that it is appropriate to remove the foot of the stockrail (assuming the prototype did!) which makes life considerably easier. I can say from experience in 4mm that getting the bottom profile of the switch to sit on the stockrail foot and keep the railheads level and smooth is "challenging" to say the least!

If and when I ever build another 7mm NG project I know which path I will be following!

Cheers

Steve

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Steve,

The simple answer for your next NG project is to use stub points - no blade planing required at all!!
You don't have use moveable crossings (as per Penrhyn & Dinorwic) as you'll use single flanged wheels that run through conventional crossings.

Just a thought!

Adrian

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Hi,

Interesting video that Brian posted the link to - Health&Safety would have had a nighmare !

Can some kind person bring me up to speed on Stub turnouts/points ? Does the switch rail pivot on something or is it hinged to the crossing vee ? I would be looking to use them on 1:32/19.05mm gauge track.

Thanks for any help.

Rob

Rob if you get in contact with George Sebastian Coleman gsebastiancoleman@...] he makes the slide chairs for doing stub turnouts for On3 how stub turnouts work is the rails leading up to where normally the switch blades would be are the rails that move the curved lead and straight lead rails that go to the frog are stationary and the moving rails move across side to side to align with the lead and stock rails on each side.




Brian
Rawbelle County Workshops
Qld. Aust.

Steve,
I use Micro Engineering code 83 rail. I have purchased 3 way planed blades from???These work well for me. I have also previously planed the base of my own handmade blades by making a jig out of icypole sticks and filing away until it looked correct. On full size track, the act of removing part of the foot to accommodate the blade will result in a significant loss of strength, probably where it is needed the most. A lot of industrial points were built this way because it is cheaper to build them. Similarly, at lot of models are built this way as it is much easier. Have a look at the blade structure of Peco points as a commercial balance of construction cost and believable appearance.

The choice of point construction is entirely yours. 3 Way planed blades would be prevalent on higher end railways (especially with passenger operations). Then would come planed stock rails, stub points, single blade points, fixed blades (person pushing the wagon shoves it in the desired direction), right down to skid plates on mining tramways.

The only real advice I can give is to do what you are comfortable with, depending on your skill levels, patience and preferred prototype. Try filing your own blades. Its not really all that hard and in the worst case you throw out 75mm of rail.

Regards,
Michael Milway

Rob,

There were several versions but the basic one is quite simple. Imagine any commercial point where the switch rails are pivoted. Take those switch rails away and cut the stock rails at the same place. The rail at the toe end now has to slide so it lines up with one pair of rails or the other. You still have the standard frog etc.

If you look on the internet for Penrhyn quarry you should find some pictures. Penrhyn used 'normal' single flanged wheels.

If you then look for Dinorwic quarry you'll find a different arrangement where the crossing was a piece of rail that turned. Dinorwic wagons wheels were flanged on both sides so a normal frog wouldn't work.

Frank

Hi Brian, Frank,

Thanks for your replies. I will do as you both suggest.

Sorry for hi-jacking Stephen's original thread.....

Rob

Rob,

Glibly I say search for Dinorwic. Well I have and though I've seen dozens of pictures of their pointwork, can I find one when I want it? However I've turned this up which shows really well how it worked. The track, not on the picture but at the far end slewed to line up with the chosen pair of rails. There was usually a linkage so when the track was slewed the piece of rail twisted to line up with the direction set. So that's the arrangement for double flanged wheels.

So for single flange you could use the same arrangement, but usually that twisting section of rail was a conventional frog. Dinorwic put locos over track like this, the locos had normal single flanges but the wagons had double flanges and the wheels were loose on the axle to allow for poor gauge maintenance in the quarry areas.

In quarries a single blade as someone put up a Taiwanese colliery were used but only by the lightest of locos, little IC's. (Officially) They were usually as in the video changed by a well aimed boot!

Hope it helps.

Whether you can get some really crude track to work in a model especially in smaller scales might be questionable. Those modelling Welsh narrow gauge say of the Tal-y-Llyn when it started under preservation in 1952 that you couldn't model the track unless you can make the grass conductive. Suitable only for dead rail modellers. Folk reckon that if they'd weeded it the track would have fallen over or gone out of gauge.

Frank

Thanks Frank, appreciate the info.

Rob

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Hi Robin,
Thanks for posting the link to the stub turnout. Picture taken from where the loco water facilities are now I think.

Rob

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Or you could use this type of points, as used in this video, all of the angles a 6°.

Yes - but they wouldn't usually run locos through such points. So you would have to create a miniature robotic horse, which would be a lot harder than planning point blades! ;-)

-- 
Brian Rumary
England
brian(at)rumary.co.uk

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-- 
Brian Rumary
England
brian(at)rumary.co.uk