Like its locomotives, all of Amtrakâs rolling stock was inherited from predecessor railroads such as Penn Central. Since there wasnât time enough to implement uniform branding on Amtrakâs fleet come May 1st, 1971, most trains were comprised of varied rolling stock from multiple railroads resulting in a colorful, or rainbow-like appearance. By 1972, Amtrak developed its Phase I livery and began repainting its fleet of heritage coaches, however due to the size and service demand of the fleet, this process took several years causing the ârainbow eraâ to last well into the decade.