On 18 September 1864, the more than 100 soldiers of the 33rd Illinois who had not reenlisted embarked on the steamer "Cassandra" along with 300 Confederate prisoners that they were assigned to guard. After reaching New York City, the Illinoisans traveled by railroad to Camp Butler on 3 October and were mustered out on 11 October. On 5 March 1865, the regiment boarded a railroad train to join the XVI Corps. That day, the train derailed at Boutte and nine men from Companies A, D, and G were killed in the wreck. Another 72 men were injured of whom 2–3 men later died. The injured soldiers were mostly in Companies A and D, but all companies had injured men except C and F at the rear of the train. A number of injured men had to be discharged because they were disabled.