Magruder's attack was accompanied by the first armored railroad battery to be used in combat. Earlier in June, General Lee had hoped to counter the approach of McClellan's siege artillery by rail by using his own weapon: a 32-pounder Brooke naval rifle, shielded by a sloping casemate of railroad iron, nicknamed the "Land Merrimack." It was pushed by a locomotive at about the speed of the marching infantry. However, even with this impressive weapon, which outgunned anything the Federal artillerists possessed, the results of Magruder's decision to send only part of his smaller force against a much larger enemy were predictable.