smokeplate

From smoke +‎ plate.

smokeplate (plural smokeplates)

1. (rail transport, obsolete) A plate fitted to the underside of a footbridge deck to deflect the smoke from a steam locomotive passing underneath.
   • 1951 October, “Notes and News: Locomotive Notes: Scottish Region”, in Railway Magazine, page 715:

     An unusual mishap on the Deeside line is described by Mr. C. J. Bowller. He writes that as the Class "B12" 4-6-0 No.1552 was entering Banchory Station on August 27, one of the smokeplates of the footbridge became detached, and struck the boiler of the engine, damaging the safety valves, and the roof of the cab.