After the arrival of the C3s, the Long Island Rail Road sold the C1s to private owners.

The rolling stock used for the LIRR's diesel service was aging, and there was political interest in offering a one-seat ride for commuters on the busy but only partially electrified Port Jefferson Branch.

The LIRR decided to solve both problems simultaneously: it would acquire several dual-mode EMD FL9 locomotives from the Metro-North Railroad and buy a small fleet of new passenger cars to go with them.

[1] The Budd Company had built the most recent additions to the LIRR's electric fleet, the M1 and M3, but by the mid-1980s, it was a subsidiary of Thyssen and exiting the railroad business.

This was due in part to the difficulties the railroad experienced with the PRR MP70 electric multiple units, which it had retired in 1972.

[11] The rebuilt FL9 locomotives allowed operation through the East River Tunnels into Pennsylvania Station.

It was designed for use at high-level platforms, so the doors sit roughly 4 feet 3 inches (1.30 m) above the rail.

On the upper and lower levels, seating is 3–2, similar to other LIRR and Metro-North cars.