45 U.S.C. § 60
Any contract, rule, regulation, or device whatsoever, the purpose, intent, or effect of which shall be to prevent employees of any common carrier from furnishing voluntarily information to a person in interest as to the facts incident to the injury or death of any employee, shall be void, and whoever, by threat, intimidation, order, rule, contract, regulation, or device whatsoever, shall attempt to prevent any person from furnishing voluntarily such information to a person in interest, or whoever discharges or otherwise disciplines or attempts to discipline any employee for furnishing voluntarily such information to a person in interest, shall, upon conviction thereof, be punished by a fine of not more than $1,000 or imprisoned for not more than one year, or by both such fine and imprisonment, for each offense: Provided, That nothing herein contained shall be construed to void any contract, rule, or regulation with respect to any information contained in the files of the carrier, or other privileged or confidential reports.
If any provision of this chapter is declared unconstitutional or the applicability thereof to any person or circumstances is held invalid, the validity of the remainder of the chapter and the applicability of such provision to other persons and circumstances shall not be affected thereby.
45 U.S.C. § 60