Wednesday, April 16, 2008

Atlas N scale Union Pacific/Sante Fe 0-8-0s...


...and the problem of quartering drivers.

"Quartering" refers to the crank points opposite those crescent moon shaped counterweight details found on the main drivers of all steam engines. The crank point on each driver is 90 degrees forward or reverse of its mate, depending on the road modeled. In real life they smooth out the rotation of the drivers by providing a counter to the pounding rods among other things. In models---unless they are live steam---they are purely cosmetic.

On most N scale steam locomotives, they are usually equipped with all geared drivers, oddly enough an innovation not regularly used in HO steam. Because each driver is interconnected with the next by an idler, quartering becomes very important in relation to the connecting rods. This is the chief reason why most folks have trouble getting a steam locomotive model to run right after disassembly for cleaning and maintenance.

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The one on top is properly quartered and aligned. The one at the bottom is as it arrived to my shop after an S.O.S. from a fellow modeler. The driver retainer plate was slightly concaved, allowing the center two drivers to slip out of gear and then out of quarter. By bending the retainer plate slightly convexed so that it would flex flat after the screws were turned in, the drivers were able to remain quartered and the beastie behaved as it should.

Ribbet counters please note that I DO know that the Indiana Harbor Belt was the only owner of this particular type of yard goat.

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