Nickname for the New York Central railroad. The NYC's major routes almost all followed river valleys; the resulting almost flat raceways allowed smooth high speed running all the way. The road's advertising made much of the good sleep a passenger would get on an overnight run over their smooth, level route from New York to Chicago, in contrast with the steep climbing that passengers on such rival roads as the Pennsylvania Railroad would experience.
The nature of the NYC's routes influenced more than advertising. The road bought no large modern power dedicated to freight service for the NYC proper (as opposed to steeply-graded subsidiary lines) after the H-10 Mikado of 1925; subsequent power were the fast and dual-duty Mohawks. Unlike fellow 'small locomotive' road, the PRR, double heading was very rare; the NYC rostered no ten-drivered road power, either.