Dear Ms. McGregor,
Thank you for posting your request on History Hub!
We searched the National Archives Catalog and located a series titled Correspondence, 3/1/1917-9/30/1927 in the Records of the Office of the Surgeon General (Army) (Record Group 112) that includes in Box 4, “310.31-1 6th Sanitary train-330.3-1 12th Sanitary Train”; and a series titled Records of Divisions, 1918-1942 in the Records of American Expeditionary Forces (Record Group 120) that includes records of the 10th Sanitary Train in Box 28. For access to and/or copies, please contact the National Archives at College Park - Textual Reference (RDT2) via email at firstname.lastname@example.org.
We also suggest that you request a copy of his Official Military Personnel File (OMPF). OMPFs and individual medical reports for enlisted men of the U.S. Army who were separated from the service after October 1912 and prior to 1955 are in the custody of NARA’s National Personnel Records Center in St. Louis. In many cases where personnel records were destroyed in
the 1973 fire, proof of service can be provided from other records such as morning reports, payrolls, and military orders, and a certificate of military service will be issued. Please complete a GSA Standard Form 180 and mail it to NARA’s National Personnel Records Center, (Military Personnel Records), 1 Archives Drive, St. Louis, MO 63138-1002.
We hope this is helpful. Best of luck with your family research!