Carter Brothers Swing Motion Trucks

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CraigH
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Re: Carter Brothers Swing Motion Trucks

Post by CraigH » Fri Jul 02, 2010 7:42 pm

Randy's correct, I wasn't mapping locations of parts, angles, or anything like that. Simply dimensioning the iron for fabrication and duplication. The schematic in the corner is simply to aid in part identification and not scaled.

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HoltSteamer
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Re: Carter Brothers Swing Motion Trucks

Post by HoltSteamer » Fri Jul 02, 2010 9:11 pm

What about how the brakes hung and attached on the trucks themselves. I want to start there but don't have any info on how they attached on the trucks. This question is refering to both the brakes and the brake rods on the trucks. Thanks

-Robert

Randy Hees
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Re: Carter Brothers Swing Motion Trucks

Post by Randy Hees » Fri Jul 02, 2010 9:30 pm

On Carter or WSLC trucks, the brake beams, which carry the brake shoes and heads are hung from outriggers off the outside of the trucks truck side frames (these are outside hung brakes)

From the brake beams the truck brake levers are hinged either a casting or forging centered on the brake beams. The two truck brake levers are connected underneath (bottom of the levers) the wheel sets via a single rod connecting them. The inner brake beam lever is connected at the top to the transoms or bolster. The top of the outer lever connects to the car brake levers.

I hope this make sense....

Randy
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CraigH
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Re: Carter Brothers Swing Motion Trucks

Post by CraigH » Sat Jul 03, 2010 4:53 pm

Robert,

Since a picture's worth a lot of words...

This first example is of a Carter 8 Ton truck without the wings Randy mentioned. This style of truck would have had body hung breaks. Fantastic on a line with gentle, broad curves. The very nature of having the breaks hung from the body limits the ability of the truck to rotate without binding on the break shoes. See the hangers labeled in red.
Carter 8 Ton.jpg
MacGreggor: "Birth" Stanford Press. Page 185. Drawn by: Robert Schlechter
The next image is of a typical truck hung break. These operate better on sharp curved roads. Since the truck assembly travels with the truck's rotation, the breaks won't bind as readily when the truck turns. There is a practical limit. The break rods and connecting gear will tighten and compress the breaks to "lock" if the trucks rotate too far. I tried this with operating breaks in 1:20.3 once. You can't use working breaks without impractically large curves at model scales.
Carter 8 Ton-Truck Hung.jpg
From: MacGregor's "Birth" Stanford Press. Page 423. Drawing by Robert Schlecter.
Last, A general drawing illustrating basic rigging without air. Break iron as illustrated in an earlier post are obviously adapted in length to suit the car's wheelbase.
Rigging.jpg
From: MacGregor's "Birth" Stanford Press. Page 120. Drawing by Herman Darr.
For a car with supplied air, pretty much any drawing with such hardware and plumbing features will work.

Hope this helps.

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Solomani
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Re: Carter Brothers Swing Motion Trucks

Post by Solomani » Wed Aug 04, 2010 9:01 pm

Craig,

Just curious what "impractically large" was?

- John

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Re: Carter Brothers Swing Motion Trucks

Post by CraigH » Mon Aug 09, 2010 3:15 pm

John,

I never really checked on the impractically large radius. For sure the scale breaks would lock up at 12' Rad and under. I tried them on 8' and whatever the BAGRS use on the portable layout modules. If I still had them I'd love to try them on anything over 12' R and find out.

I disassembled them and used the trucks so they no longer exist. Tried a mock-up for working Millers Coupler too. Non-scale turns end up pulling cars off rails. The Millers need chains and buffers to keep the cars positioned correctly and prevent the couplers from disengaging just like the real ones. The tight turns cause that system to fail. Like the breaks, I no longer have the Miller mock-ups.

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Re: Carter Brothers Swing Motion Trucks

Post by Randy Hees » Tue Aug 10, 2010 2:43 pm

Just curious what "impractically large" was?

- John
At one time we had a kink in a curve at Ardenwood that was just about 120' radius... at that point the wheel flanges were touching the truss rods... so for the real thing, 120' was about as tight as you wanted to go. I believe that WSLC had some curves that were tighter... according to Baldwin, a 8-18c locomotive needs a minimum of 240' radius... about double that (but Dan Markoff says Eureka will go around a tighter radius, slowly, so wyes and such can be tighter...

In O 120' is 30" radius, 240' is 60"
Randy Hees

Director, Nevada State Railroad Museum, Boulder City
Railway Preservation News http://www.rypn.org
Chasing old trains where ever I may find them...
http://randyhees.blogspot.com/

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