Adjustable gauge

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Posts: 26
Joined: Mon Jul 31, 2017 8:24 pm
Location: Vermont

Adjustable gauge

Post by thunderskunk » Sun Sep 03, 2017 8:37 am

Hey folks,

I've seen a few engines for sale where the owner says they can regauge the locomotive from 7.5 to 7.25 somewhat easily. How does this happen? Do you design it with 1/8" space on either side starting at the crosshead and leave spacers on either end of the drivers? I just read the post on the Class A 1239 build with the conical couplings. Is that a viable way to hold drivers and maybe truck wheels to be easily switched between gauges?

I don't have a local track, the closest is 7.25" in Canada and I have friends in St Louis on 7.5" track. In the end, I'll probably end up just in 7.25, but if it's a common thing without too much engineering crazyness, it'd be cool to incorporate.

If there is a topic on this, please, by all means let me know. I'm still sifting through the forum page by page when I have time.

"We'll cross that bridge once we realize nobody ever built one."

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Location: New Jersey

Re: Adjustable gauge

Post by Trainman4602 » Sun Sep 03, 2017 9:47 am

Hi Matt

I have designed several Locomotives and other components for the hobby. As a supplier when designing I must consider both gauges. This presents some difficulty. For example the piston centers of the cylinders on a conventional locomotive must be out far enough to accommodate the wider gauge. The trailing truck same but an outside wheeled lead truck must accommodate the smaller gauge. I generally make the frames 6 inches over the out side.

Now when some one says that it is "Easily re gauge" well look at these things before you buy. Then there is the brake rigging the more complicated the worse it becomes.

Don't quote me on this but Tom Miller recently sold his Big Boy to someone in New Zealand they run on 7.25 Toms engine is strictly scale to 1.6 so the above mention sore spots where a problem when trying to move the wheels inward.

It certinatly can be done but this are the areas to look and when designing or buying.
Last edited by Trainman4602 on Sun Sep 03, 2017 9:55 am, edited 1 time in total.

James Powell
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Joined: Fri Oct 28, 2011 10:42 pm

Re: Adjustable gauge

Post by James Powell » Sun Sep 03, 2017 9:52 am

I'm faced with this- dad's Dart (built by Harry Allen) is 7.25. I live out west- where 7.5 is king.

The answer is it depends. I know that people have made engines where the drivers are threaded, so that they can be turned to the current gauge. (one turn each...). I am also aware that logging type locos with gear/chain drive are easy enough to change the drivers on, complete with new axles & gears. If the engine has NOT been converted from one gauge to the other, I would not think of it as being "easy", because it is a unknown as to how easy it will be to do it.

I would suspect outside framed engines are also at an advantage here, because there are more ways to deal with having to slide a wheel (or both) by the distance than an inside framed engine. Lots to ponder,


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