traversing platform

from The Collaborative International Dictionary of English v.0.48

Traversing \Trav"ers*ing\, a.
   Adjustable laterally; having a lateral motion, or a swinging
   motion; adapted for giving lateral motion.
   [1913 Webster]

   {Traversing plate} (Mil.), one of two thick iron plates at
      the hinder part of a gun carriage, where the handspike is
      applied in traversing the piece. --Wilhelm.

   {Traversing platform} (Mil.), a platform for traversing guns.
      [1913 Webster]