FrankJohnson Wrote:
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> I thought that the K37'S shared the same pony
> truck as the 36's but the trailing truck was the
> same as the 28's?
K-28's and K-37's use the same design trailing truck, but not the same truck. These engines use what is known as a "Cole Trailing Truck" where the weight of the engine is transferred to the truck through a pair of sliding steel plates, one on the truck, the other on the frame. The spring rigging on the engine places the weight on the plate. Centering of the truck is provided by coil springs behind the truck frame.
K-36's use a "Hodges Trailing Truck" where the weight is transferred to the truck by swing links from the trailing truck springs. The swing links provide the centering of the truck. Baldwin had a patent on the Hodges design and the Rio Grande would have been required to get a license to use it, and probably pay BLW a royalty on each engine.
All three classes use the same pilot truck.