five railroads connected with Petersburg prior to the Civil War
Source: US War Department, Atlas to accompany the official records of the Union and Confederate armies, Southeastern Virginia and Fort Monroe Showing the Approaches to Richmond and Petersburg (1862)
Only three major Union campaigns were conducted without relying upon railroads to supply the northern armies. Gen. George McClellan relied upon shipping to supply his Peninsula campaign in 1862. In 1864, Gen. William T. Sherman abandoned his long supply line and marched from Atlanta to Savannah without rail support. Also in 1864, Federal resources were finally sufficient for Genenal Ulysses S. Grant to conduct his Overland Campaign, from the Rappahannock to the James rivers, without rail support. In contrast to 1861, Grant's "On to Richmond" march in 1864 did not require use of the Orange and Alexandria Railroad to Gordonsville and the Virginia Central Railroad south of that point to Richmond.
Grant's campaign in 1864 stalled outside of Richmond, and he spent nine months trying to capture Petersburg.
Why Petersburg, instead of the capital of the Confederacy at Richmond? Petersburg was the railroad hub of Central Virginia. Essential supplies and reinforcements reached Richmond from the south through Petersburg. Without supplies shipped via railroad through Petersburg, the Confederate government could not survive in Richmond.
five railroads converged on Petersburg, and blocking supplies flowing through Petersburg ultimately forced the Confederates to evacuate Richmond in April 1865
Source: Library of Congress, Military topographical map of eastern Virginia
General Lee fought for months to defend his supply line. During the siege of Petersburg, General Grant used his superior resources to gradually extend his lines south and west to encircle Petersburg. He first cut the Norfolk and Petersburg Railroad, then the Petersburg and Roanoke Railroad to block the Confederates from receiving supplies by rail from the supply depot at Weldon, North Carolina.
Grant's forces gradually moved to encircle Petersburg, and finally seized control of the South Side Railroad in the battle of Five Forks on April 1, 1865. At that point, with no remaining railroad connection, Lee abandoned Petersburg and the Confederate government abandoned Richmond.
The Union Army's direct frontal attacks on Richmond failed in 1862 and 1864, but succeeded when General Grant swung south of the James River and cut off the capital's supplies brought via Petersburg's railroad network. Jefferson Davis, with the Confederate gold, fled south on the Richmond and Danville Railroad. He took the last trains to leave the Richmond station before the Union cavalry cut that line as well.
the 1864-65 Siege of Petersburg was designed to cut the transfer of supplies via railroad
Source: Library of Congress, E. & G. W. Blunt's corrected map of the seat of war near Richmond, July 10th, 1862
The Richmond and Danville Railroad tracks and locomotives were so worn out that Jefferson Davis's train averaged only 9mph in its 140-mile, Sunday night flight to Danville.1
On the way, at Burkeville Junction it passed two trains loaded with supplies for Lee's Army at Petersburg. The trains withdrew to Farmville, reducing the risk of Union capture but leaving the Confederate Army short of rations.2
in 1865, the South Side railroad linked Petersburg with Lynchburg and intersected the Richmond and Danville Railroad at Burkeville ("Junction")
Source: Library of Congress, Map of the proposed line of Rail Road connection between tide water Virginia and the Ohio River at Guyandotte, Parkersburg and Wheeling
this 1869 map includes a second Appomattox station, but the famous one was on the South Side railroad and not the Richmond and Danville Railroad in 1865
Source: Library of Congress, Map showing the Fredericksburg & Gordonsville Rail Road of Virginia
the Richmond and Petersburg Railroad bridge over the James River was burned by Confederates on the evening of April 3, 1865 after Richmond was evacuated
Source: Smithsonian Institution, Plate 88. Ruins of Richmond and Petersburg Railroad, Across the James (Gardner's Photographic Sketchbook of the War, Vol. II)
Union cavalry destroyed tracks leading into Petersburg in 1864
Source: Library of Congress, Destruction of Genl. Lees lines of Communication in Virginia by Genl. Wilson (by Alfred R. Waud, 1864)
in the last days of the Civil War, Confederates destroyed railroad equipment at Petersburg that would be needed during Reconstruction
Source: Library of Congress, Bridge on the Appotomax [sic]--Train of Cars and workshops burned by the rebels on evacuating Petersburg (by Alfred R. Waud, 1865)