23 C.F.R. § 646.206

(a) Projects for the elimination of hazards, to both vehicles and pedestrians, of railroad-highway crossings may include but are not limited to:

(1) Grade crossing elimination;

(2) Reconstruction of existing grade separations; and

(3) Grade crossing improvements.

(b) Other railroad-highway projects are those which use railroad properties or involve adjustments to railroad facilities required by highway construction but do not involve the elimination of hazards of railroad-highway crossings. Also included are adjustments to facilities that are jointly owned or used by railroad and utility companies.