It's the beginning of the day in Chicagolandia and I get to start it by scouring mechanical drawings. Perfect! Also, I'm no expert, I only see what I see.
According to the engineering dept's drawings of both K-28 and K-37 trailing trucks, they are nearly identical. There are some differences though. The distance between the axle center line and radius bar crosstie pin on the K-28 truck is 66" and on the K-37 is 74". Most other differences are quite a bit more subtle than that, mostly fractions. The cross sections are virtually identical except for the wheel width on the 28 is 5.5" and on the 37 is 5.625". I do recognize that these drawings are dated 1923 and 1928 respectively, and as time passed modifications were made as applied to the real world.
I could better describe the other minor differences if I knew what the parts were called, but I think the statement that they are the "same" is fair for the purposes of this discussion.
Mike McKenzie
Frankfort IL
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