Alcohol / Drug testing is a complex subject and you can read all about it in the following link:
Quote:
To summarize, safety-sensitive employees are subject to pre-employment, post-accident, random and reasonable suspicion testing. Railroads have to develop and submit their programs to FRA including the system for randomly selecting employees for the unnounced random tests. An employee such as the conductor may be perfectly within his rights to take certain otherwise-prohibited substances if properly prescribed by a doctor. Should an employee show a positive test, the results are reviewed by the Medical Review Office prior to any decision about penalties. The programs are subject to FRA audit and I suggest there are no clubby arrangements. The UP conductor undoubtably is aware of the testing requirements (railroads are required to provide training) and should know that evidence of marijuana use can stay in one's system for days if not weeks after use.