What is a top center plate?

NW Mailing List nw-mailing-list at nwhs.org
Mon May 18 08:02:06 EDT 2020

A Top Center Plate or Body Center Plate is the bottommost portion of a
rail car bolster. It is the part that mates with the "Bottom Center Plate"
which is the topmost portion of a truck assembly. Together the top and
bottom center plates transfer the weight of the car from the body to the
truck. The bottom center plate rotates relative to the top center plate
as the car negatiates curves.  A "Center Pin" or "King Pin" goes through
the center of both to keep them centered against each other.

When you screw the trucks to the underframe when assembling an Athearn
blue-box kit, you're using a center pin to connect the top and bottom
center plates to each other.

To confuse things even more, as least one vendor's drawings refer to the
Top Center Plate as the "Bolster Bottom Center Plate".

Joe Shaw
Christiansburg, VA

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