What’s A KIP?

There are a lot of railcars wheels are being replaced due to “High KIPs”.  We toss these terms around without really understanding what they mean.

So what is a KIP?  There are a couple of definitions of a “kip”.

One definition is “a gymnastic exercise performed starting from a position with the legs over the upper body and moving to an erect position by arching the back and swing the legs out and down while forcing the chest upright”.  I can’t even figure that out much less try it without major injury to this old body.

90 KIP force is greater than 2 1/2 times the fully loaded 286K GRL wheel at rest

For use in the rail industry, the term KIP is engineering slang for 1,000 pounds-force.  So, a 90 KIP wheel is a wheel that is generating 90,000 lbs. of force when measured by a wheel impact detector.

For comparison, the wheel static load for a fully loaded 296,000 Lb. GRL railcar is 35,750 lbs at each wheel.  So the 90 KIP force registered for a single wheel is greater than 2 1/2 times the static load.  This force goes two ways.  One way is into the track and track structure, not a good thing for the track.  This force is also going into the railcar – the old “equal and opposite” equation; also not a good thing for a railcar.

So yes – High KIP wheels are a major cost driver for car owners.  But so are high forces going into the track and going into the railcar.

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