hammer blow

plural hammer blows · alternative hammerblow

1. A blow with a hammer.
2. rail transportA pounding of the rails by the driving wheels of a steam locomotive caused by the inertia of unbalanced parts.

   1 more example

   The balancing of the engine is unusual, with the rotating masses fully balanced and 40 per cent of the reciprocating masses statically balanced by lead weights in the coupled wheels; the reciprocrating balance weights are in the same phase on both sides of the engine. This system saves balance weight and reduces the wheel hammer-blow.

   1959 September, P. Ransome-Wallis, “The British Railways Class "9" 2-10-0s”, in Trains Illustrated, page 419