 The AEF Siberia included the U.S. Army's 27th and 31st Infantry Regiments, plus large numbers of volunteers from the 13th and 62nd Infantry Regiments along with a few from the 12th Infantry Regiment.Set up to operate the Trans-Siberian railroad, the Russian Railway Service Corps was formed of US personnel.Although General Graves did not arrive in Siberia until September 4, 1918, the first 3,000 American troops disembarked in Vladivostok between August 15 and August 21, 1918.