49 U.S.C. § 10721
Government traffic
A rail carrier providing transportation or service for the United States Government may transport property or individuals for the United States Government without charge or at a rate reduced from the applicable commercial rate. Section 6101(b) to (d) of title 41 does not apply when transportation for the United States Government can be obtained from a rail carrier lawfully operating in the area where the transportation would be provided.
(Added Pub. L. 104–88, title I, § 102(a) , Dec. 29, 1995 , 109 Stat. 819 ; amended Pub. L. 111–350, § 5 ( o )(4), Jan. 4, 2011 , 124 Stat. 3853 .)