Found these on Google
Thomas Bulla The Stationmaster
Many articles about Indiana Underground Railroad
Thanks so much Alice!
Dear Ms. Pillari,
Thank you for posting your request on History Hub!
Because the Underground Railroad was a private and secretive organization, the National Archives does not have any equivalent of a personnel file or roster regarding his participation in the Underground Railroad. The records NARA might have regarding him are much the same as those for researching other private individuals. Please see Resources for Genealogists for information about the types of records that NARA might have. There is no name index covering the entirety of NARA holdings, so each set of records would have to be searched separately. For more information about specific types of records, you may post a follow-up question on History Hub or contact NARA privately via our contact form.
We suggest that you also contact state, university, and local archives, libraries, history museums, and historical societies.
You also may be interested in the following page from the University of Notre Dame on Thomas Bulla and the pages from the Indiana Department of Natural Resources on Underground Railroad Sites: South Bend and Underground Railroad.
We hope this is helpful. Best of luck with your research!