(a) Each railroad may, at its own discretion, elect to conduct Federal reasonable cause testing authorized by this subpart. If a railroad chooses to do so, the railroad must use only Federal authority for all reasonable cause testing that meets the criteria of §219.403. In addition, the railroad must notify its regulated employees of its decision to use Federal reasonable cause testing authority in the employee educational policy required by §219.23(e)(5). The railroad must also provide written notification of its decision to FRA's Drug and Alcohol Program Manager, 1200 New Jersey Ave. SE., Washington, DC 20590.

(b) If a railroad elects to conduct reasonable cause testing under the authority of this subpart, the railroad may, under the conditions specified in this subpart, require any regulated employee, as a condition of employment in regulated service, to cooperate with breath or body fluid testing, or both, to determine compliance with §§219.101 and 219.102 or a railroad rule implementing the requirements of §§219.101 and 219.102. This authority is limited to testing after observations or events that occur during duty hours (including any period of overtime or emergency service). The provisions of this subpart apply only when, and to the extent that, the test in question is conducted in reliance upon the authority conferred by this section. A railroad may not require an employee to be tested under the authority of this subpart unless reasonable cause, as defined in this section, exists with respect to that employee.