After the fall of Atlanta in September 1864, the Confederate Army retreated and turned to attacking Federal supply lines north of the city. On October 4, Confederate Major General Samuel G. French's division of 3,276 men was ordered to march north from Big Shanty and attack the Federal garrison of 976 troops defending the railroad cut at Allatoona Pass. After an all-night march, French's troops surrounded the area and attacked on the morning of October 5, intending to overrun the Federals, fill the railroad cut with debris, and cut off supplies to the Union Army in Atlanta. Unknown to French, Federal reinforcements had arrived only hours before on a train from Rome, bringing General John Corse and 2,025 additional soldiers, many armed with Henry repeating rifles, whose rapid fire gave the Federals a decisive advantage. After hours of fierce fighting and the near-capture of the Federal positions, French withdrew when warned that his division might be cut off from the main Confederate army. In a matter of hours, 1,603 men from both sides were killed, wounded, or missing, and with a 35% Union casualty rate and 27% Confederate casualty rate, the battle ranked among the war's most deadly and stubbornly contested engagements.