The Railroad Redoubt was a Confederate fortification built to protect a vital entrance to the city — in this case the Southern Railroad of Mississippi.
On May 22, General Grant ordered a second major assault against the formidable Confederate positions. Union forces began their carefully planned attack with a fierce artillery bombardment, followed by the advance of the infantry.
Tour Stop 13 - Railroad Redoubt
Unlike other points along the Confederate defense line, the blue-clad soldiers found that the redoubt's southeast angle had been partially destroyed by the artillery bombardment. Union soldiers commanded by Sgt. Joseph E. Griffith of the 22d Iowa were able to exploit this brief breakthrough and quickly entered the redoubt in an attempt to storm the Confederate earthworks. The Confederates counterattacked and called up reinforcements. Waul's Texas Legion arrived to drive out the Federals and "seal the breach."
Although Union forces sustained heavy losses, Griffith managed to withdraw, taking a dozen prisoners with him. By evening, the Federals had returned to their lines. There were no further attacks on the Railroad Redoubt, and mining operations commenced. By the time of the surrender on July 4, 1863, approach trenches had reached the redoubt's outer ditch.