The introduction of mainline diesel power in the late 1940s brought the famous "lightning stripe" to New York Central's image. The conservative but striking motif could not be applied to the Dreyfuss-designed bullet-nose J-3s or C-1s, but it could be applied to the older "inverted bathtub" streamlined style of the NYC's K-5b Pacifics, Nos. 4915 and 4917, introduced on the Mercury and then shifted to the James Whitcomb Riley. By the time the "lightning" motif had appeared, a longer and heavier Riley was powered by Hudsons and the two shrouded K-5s served on a Detroit-Cincinnati run in competition with the Baltimore & Ohio's Cincinnatian, likewise powered by streamlined Pacifics.

A New York Central "Fantasy Steam" Feature

In 2012-13, Precision Scale produced a limited run of the NYC's K-5b in HO scale with this imaginary "lightning stripe" livery. A viewer shared the image below of this model.