N.H. Rev. Stat. § 246:11
The governmental authority responsible for maintaining a highway shall place and maintain warning signs on every highway approaching a crossing at grade of such highway and the tracks of a railroad, at a reasonable distance on each side of such crossing. The department of transportation shall prescribe the standards for warning signs for highway grade crossings. If any governmental authority, except the state, shall neglect to comply with the requirements hereof it shall forfeit $1 for each day during which it shall neglect to place or maintain each sign required hereby to be placed or maintained by it, such forfeiture to be recovered in an action of debt, in the name and for the use of the state.
RSA 246:11
1915, 4:1. PL 249 :15. RL 299:18. 1951, 203:58 par. 11. RSA 373:11. 1977, 41:1. 1985, 402:6, I(e)(5).