The 2400-series cars (numbered 2401-2600) were manufactured by Boeing-Vertol of Philadelphia, Pennsylvania and first delivered to the CTA in 1976 100 were ordered originally, with an option for an additional 100 (which was exercised, and the additional cars delivered through 1978). Currently, the cars are reaching the end of their expected service lifetimes and are to be replaced with the new 5000-series cars starting in 2010.
The first cars for the 'L' in many decades to feature sliding rather than "blinker" doors, the 2400-series also features smooth steel exteriors, ideal for decals and, in many cases, advertisements. As delivered, the cars featured a red, white, and blue color scheme on the front and rear of the cars, as well as stripes along the sides. These were modified several times over the years and the color has been removed from most cars at present, leaving them unpainted to match the bare stainless steel scheme of the rest of the fleet. Some cars feature advertising and cars 2401–2422 are "work" cars which are identified by red and white striping along their sides as well as on the front and rear of the cars.
They were rehabbed by Skokie Shops between 1987 and 1995.