N.H. Rev. Stat. § 246:3
Any order issued under RSA 373:2 shall provide for the apportionment of the cost (1) between the railroads in interest if the crossing eliminated or improved is a railroad crossing or (2) between the railroad and the state if such crossing is located at the intersection of a railroad and a state highway, trunk line or state-aided highway, or (3) between the railroad and the municipality if such crossing is located at the intersection of a railroad and a highway other than those above specified. In making such apportionment, the department of transportation shall give due consideration to whether the railroad or the highway was first constructed, to the nature and volume of highway traffic, to the number of trains operated by the railroad at the crossing, and all other relevant facts and circumstances. After such reconstruction, the abutments and superstructure of the bridge or underpass shall be maintained by the railroad; but the department of transportation may direct that the wearing surface of a highway at the crossing be maintained by the state or by the town or city whenever it finds that justice so requires.
RSA 246:3
1937, 123:1. RL 299:4. 1951, 203:58 par. 3. RSA 373:3. 1985, 402:6, I(e)(5).