Author Topic: Tasmanian 2-foot gauge...  (Read 10973 times)

Stephen Hussar

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Tasmanian 2-foot gauge...
« on: February 06, 2010, 05:25:40 PM »
Photos of a switch on the Wee Georgie Mine Ry in Tasmania -sent in by Wayne Laepple... thanks, Wayne!




James Patten

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Re: Tasmanian 2-foot gauge...
« Reply #1 on: February 06, 2010, 07:16:58 PM »
How does that switch work?

Looks like a stub switch, but I can't see any way for the wheels to follow the rail once the rails move - that frog on the right won't move the wheels at all.

Wayne Laepple

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Re: Tasmanian 2-foot gauge...
« Reply #2 on: February 06, 2010, 07:29:27 PM »
It looks to me like the two left hand rails would move together, and the angled one on the "inside" would act like a guard rail and push the back of the left wheel over, thus pulling right wheel over as well. Some trolley lines had single point switches that worked almost the same way, only it was the point that would force the opposite wheel away from the point of the frog. Maintaining exact gauge was necessary for either type to work properly. I sent these photos to a couple of track experts I know, neither of whom had ever seen such a thing.

Mike the Choochoo Nix

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Re: Tasmanian 2-foot gauge...
« Reply #3 on: February 07, 2010, 09:17:13 PM »
What we have here boys is a Wharton Safety Switch. To quote from Elements of Railroad Engineering by Raymond. "This switch provides for a continuous main line. It is a split switch, but with movable rails in the turnout instead of the main line, the wheels being lifted on an incline so the flange will cross over the main line rail."

Mike Nix
P.S.
I'm having problems attaching a scan, I'll try it as a new topic. "Wharton switch"
Mike Nix

Bill Fortier

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Re: Tasmanian 2-foot gauge...
« Reply #4 on: February 08, 2010, 12:36:42 AM »
Wharton switch? Um, no. Wayne has it right. When lined for the diverging route the outer, or back, face of the inner point rail serves to direct the wheel in the desired direction. The mate on the right doesn't move at all, and the wheel rides through the gap on its flange. It's sort of a single point/stub switch hybrid.

A single point street switch for an industrial siding:



A tramway/streetcar single-point switch does without the flange guard found on the industrial switch point.

An interesting feature of that Tasmanian track is the means of securing the rail to the sleepers. The "spikes" are remarkably similar to hold-fasts used on woodworking benches.

Mike the Choochoo Nix

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Re: Tasmanian 2-foot gauge...
« Reply #5 on: February 08, 2010, 10:12:12 AM »
Wharton switch, Um, yes. I found a link with drawings like I tried to attach.
Notice that the flange on the inside rail has to go over the main line rail.
The street car switch has its point on that rail. The main line has no breaks in it excepting the frog.

http://mysite.du.edu/~jcalvert/railway/wharton.htm

Mike Nix
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Mike Fox

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Re: Tasmanian 2-foot gauge...
« Reply #6 on: February 08, 2010, 10:13:53 AM »
Only one moving point in that switch. But 2 frogs. I have seen one in a photo someplace else and had to study it. Works just as Wayne described. Very simple. I bet the angle cut on the main line rail was an afterthought.

Actually the B&B had something similar to this. The Bryant Switch. Only it was a stub on one side with a point on the other.
« Last Edit: February 08, 2010, 10:21:02 AM by Mike Fox »
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Mike Fox

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Re: Tasmanian 2-foot gauge...
« Reply #7 on: February 08, 2010, 10:18:07 AM »
That Wharton Safety switch doesn't look all that safe to me. I bet it's a rough ride when that flange goes over the head of the rail.
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Nick Griffiths

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Re: Tasmanian 2-foot gauge...
« Reply #8 on: February 08, 2010, 01:27:40 PM »

An interesting feature of that Tasmanian track is the means of securing the rail to the sleepers. The "spikes" are remarkably similar to hold-fasts used on woodworking benches.

On this side of the pond they're known as "elastic spikes" and are used to prevent rail creep on gradients, as the tension in the driven spike grips the rail foot positively.  The spike is made from one piece of steel doubled over and formed to shape.  IIRC the diameter of the predrilled hole in the tie/sleeper is important.

HTH

Nick

Bill Fortier

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Re: Tasmanian 2-foot gauge...
« Reply #9 on: February 08, 2010, 01:40:15 PM »
That Wharton Safety switch doesn't look all that safe to me. I bet it's a rough ride when that flange goes over the head of the rail.

A bit of a bump, probably, but the description claims it's for low-speed operation. As near as I can figure it, the divergent (outside) rail engages the outer edge of the tread and lifts the wheel so the flange clears the tangent rail head. The moving point/guard rail assembly keeps things laterally correct. It's an uncomfortably complex design, to be sure.

The Tazmanian switch, however, isn't a Wharton. The mate side of the switch has no moving parts, and the point assembly has the one regular throwbar and no need or means to lift a wheel. Here's the same switch in the divergent position:


Bill Fortier

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Re: Tasmanian 2-foot gauge...
« Reply #10 on: February 08, 2010, 01:45:20 PM »

An interesting feature of that Tasmanian track is the means of securing the rail to the sleepers. The "spikes" are remarkably similar to hold-fasts used on woodworking benches.

On this side of the pond they're known as "elastic spikes" and are used to prevent rail creep on gradients, as the tension in the driven spike grips the rail foot positively.

Sort of a precursor to the Pandrol fastener.

Mike the Choochoo Nix

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Re: Tasmanian 2-foot gauge...
« Reply #11 on: February 08, 2010, 08:21:50 PM »
Ahh ! The main rail moves. So it's a hybrid, half stub and half point.
Mike Nix
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