The New Haven was an early proponent of piggyback service, running between its Harlem River Terminal and Boston. The trains themselves were marketed as Trailiners, and they were the hottest freights on the system. The Merchant's Limited and Yankee Clipper were the hot daytime trains, and HB-5/BH-6 and HB-7/BH-8 were the hot nighttime trains. How hot were they? Well, they swapped power at New Haven Union Station rather than get delayed dealing with Cedar Hill Yard, and, if push came to shove, First Class trains had to get out of their way, at least on the West End. In later years both HB-8 and BH-7 had EP-5s for power between Harlem River and New Haven.
It was both a freight program and a marketing campaign. The truck company has no connection.
Ex-NYNH&H SS Opr