Builders in the United States began applying steam whistles to locomotives in 1836. The United States government finally mandated use of whistles on all locomotives, and use of standardized signals, in 1876. The first whistles used in the U.S.A. were on a pair of New Haven Railroad locomotives built in 1836 under the supervision of general superintendent George Washington Whistler (whose son James McNeil Whistler painted Whistler's Mother). They were described as "shrill" and "unearthly."