Hi all,
Given that the mechanism on a Shay (and Climax/Hiesler) locomotives are based around a geared ‘driveshaft’ turning the wheels, as opposed to a rod turning counterbalanced wheels, would the acceleration of a geared locomotive be quicker than that of a conventional locomotive?
Thanks in advance,
tbdanny.
In a word, yes. Torque’s the key in acceleration from a standing stop. In addition to the gearing, most Shay’s had 3 cylinders rather than 2 which would give more even torque.
Get a car with a manual transmission and try to accelerate it from a standing stop in 3rd gear. Then try it in first. You’ll see the difference.
Andre
From first-hand experience, I found it relatively easy/quick to accelerate a Shay, even with load, to its maximum or operating speed (10 to 15 m.p.h.). Nevertheless, I’m not prepared to say it would necessarily accelerate faster than a rod locomotive, particularly if it wasn’t pulling a very heavy load. But if I was to bet, I’d put my money on something like a 63-inch-drivered Mogul with a light load over a Shay with similar load.
Mark
With the Shay, there are six beats for every turn of the drive rod. Geared down a lot.
I do know many Climax locos, which are two cylinder, had two speed transmissions.
With geared locos, speed or acceleration was hardly ever an issue. Just slow strong pulling action. Most track was fairly rough and steep gears with tight radius curves. Maybe 8 to 10 degree grades with 30 degree radius curves. How much geared locomotives could haul was much more important than speed or acceleration. I have photos of geared locos hauling tree trunks between the rails and not using any rolling stock. It was rough, brutal work.
Many geared locos had wheels that look like rims from cars with no tires and used “pole roads,” that is, tree trunks laid end to end to make a “railroad track” out of the tree trunks.
I am not sure anyone tries to model track work for the logging railroads. At least I have never seen any.
Rich
My Shaymaxfeisler will turn 0 to 60 in 3.6 . . . . . . . . . .
. . . . . . . . . . minutes.
There were two cylinder Shays as well - the 18-tonners used on the 762mm gauge Alishan Forest Railway (Taiwan) come to mind.
Interesting.
Some of the curves were a lot tighter than 30 degrees! Some, on temporary logging spurs of the Kiso Forest Railway were 30 meter radius. Interestingly, the Kiso Rintetsu never owned a Shay. They started with a bunch of 0-4-2T and 0-6-0T teakettles, and graduated to 4-wheel industrial switcher-pattern diesel-mechanicals. IIRC, there were only two 4-axle diesels on the property when I visited it in 1964.
In many cases, how much a locomotive could hold back on a steep downgrade was more critical than any other consideration. A lot of the disconnects used in the early days had no brakes of any kind.
Pick your logging railroad with care. True, some of them were pole roads with sp
Thats hard to say because shays go 1/8th the speed of toenail growth. 
I would say they both accelerate in their own special way.
Not always true, Anaconda Copper’s 3 truck is hauling the mail. [:D]
Express mail. [(-D]