battering train

plural battering trains

1. historicalgovernmentA train of heavy artillery, such as battering rams and catapults, for siege operations.

   When the fire reached this barrier, it was compelled to pause, until a concentration of its heat could overcome the moisture, like an army impatiently waiting the operations of a battering train, to open its way to death and desolation.

   1823, [James Fenimore Cooper], chapter XXXVII, in The Pioneers, or The Sources of the Susquehanna; […], volume (please specify |volume=I or II), New York, N.Y.: Charles Wiley; […], →OCLC

   1 more example

   Be that as it might, numberless great guns, whose thunder had long been the voice of battle,—the artillery of the Armada, the battering-trains of Marlborough, and the adverse cannon of Napoleon and Wellington,—were trundled into the midst of the fire.

   1844, Nathaniel Hawthorne, “Earth’s Holocaust”, in Mosses from an Old Manse. […], part II, New York, N.Y.: Wiley and Putnam, published 1846, →OCLC, page 141