Fighting Opioid Abuse in Transportation Act This bill directs the Department of Transportation (DOT) to publish a final rule revising regulations for alcohol and controlled substances testing to designate rail mechanical employees and yardmasters as railroad employee responsible for safety-sensitive functions. The General Accountability Office shall review DOT's Drug and Alcohol Testing Management Information System and submit to Congress a report on the review, including appropriate recommendations. The Department of Health and Human Services (HHS) shall determine whether a revision of the Mandatory Guidelines for Federal Workplace Drug Testing Programs to expand the opiate category on the list of authorized drug testing to include fentanyl is justified, based on the reliability and cost-effectiveness of available testing. If the expansion of the opiate category is determined to be justified, HHS shall publish a final notice of the revision of the Mandatory Guidelines for Federal Workplace Drug Testing Programs to expand the opiate category on the list of authorized drug testing to include fentanyl. If the expansion of the opiate category is determined to be justified, and DOT concurs with that determination, DOT shall publish a final rule revising regulations for procedures for transportation workplace drug and alcohol testing programs to include fentanyl in DOT's drug-testing panel, consistent with the Mandatory Guidelines for Federal Workplace Drug Testing Programs as revised by HHS. HHS shall: (1) submit to Congress a report on the status of the hair testing guidelines, and (2) publish a final notice of the Mandatory Guidelines for Federal Workplace Drug Testing Programs using Oral Fluid.