City Point became a crucial Civil War logistical center, serving as headquarters for the United States Armies and as the supply base for Union forces fighting at Petersburg and Richmond. Soon after Union forces arrived, the 900-member United States Railroad Construction Corps began building the warehouses and wharves needed to handle supplies and war material for 100,000 soldiers in the Army of the Potomac and the Army of the James. The City Point Railroad, originally built in 1838, was repaired and later extended south and west of Petersburg, restoring a rail link to the city and connecting the military supply depot directly with soldiers on the front lines. In just twenty-two days, the army completed the first stage of the railroad and began running trains on a full schedule. Construction Corps workers and additional carpenters, blacksmiths, and laborers were quartered and employed throughout the area, while railroad cars brought from the north carried supplies on a regular schedule to the siege lines around Petersburg eight miles away.