Background Due to concerns about diesel emissions in the
East River Tunnels and the underground tracks of
Grand Central Terminal and
Penn Station, passenger trains entering New York City have long been required to use electrical power, as coal and later diesel exhaust would pose a hazard to human health in the confined underground spaces. The ban was originally enacted by the city in 1903, and in response the
New York Central Railroad installed
third rail electrification on the
Harlem Line, which New Haven trains used to reach Grand Central. To allow its own service to Grand Central, New Haven trackage between
Woodlawn and
New Haven, Connecticut, east from Grand Central, was electrified at 11,000 volts, 25 Hz AC overhead, with all catenary installed by 1914. The New Haven's pioneering system was used as an example for electrification projects by other railroads, including on the Northeast Corridor between New York and Washington, D.C. Plans to extend the electrification eastward towards Boston were never realized due to the railroad's financial troubles. To allow passenger trains to travel to New York City from non-electrified lines without requiring a change of locomotives, the New Haven Railroad sought a class of locomotive that could switch between diesel and electric power on the fly. A replacement was also due for the railroad's 60
ALCO DL-109 locomotives built in the 1940s. Introduction of a new dual-mode locomotive also aligned with railroad president
Patrick B. McGinnis' plans to eliminate the railroad's electrification system east of
Stamford, Connecticut, and scrap its entire fleet of pre-1955 electric locomotives, in a cost-cutting measure described by author Scott Hartley as "ill-advised". Key to the plan was eliminating the aging
Cos Cob Power Station, built in 1906.
Design The earliest attempt at developing a dual-mode locomotive to meet this need began with a proposal to gut the internals of the DL-109s and install both a new diesel engine and equipment to collect electrical power from the
third rail via
contact shoes and deliver it to the
traction motors. The proposal would also save money by reusing existing equipment and eliminating the cost of buying new locomotives. However, it was found unworkable because the weight of the resulting locomotive was estimated to exceed the weight restrictions on the
Park Avenue Viaduct in New York City. Afterwards, both
ALCO (manufacturer of the DL-109s) and
Fairbanks-Morse submitted proposed dual-mode locomotive designs to the New Haven; neither proposed design was within the weight limit for the Park Avenue Viaduct.
EMD's answer was a new locomotive based on their existing
EMD FP9, but lengthened to accommodate additional equipment, such as a larger train heating steam boiler, extra electrical equipment, and contact shoes for drawing power from a third rail. The resulting design was named the FL9 ("L" indicating "long"). The FL9s were the final members of the long-running
EMD F-unit line, in production since 1945. Due to the additional weight and existing weight restrictions on the Park Avenue Viaduct, the locomotive was equipped with a three-axle rear truck, giving it a
B-A1A wheel arrangement in the
AAR system (indicating the middle axle of the rear truck is unpowered).
Flexicoil trucks were used for the rear truck due to this type of truck having more room for fitting the
third rail shoes. The locomotives measured in length and weighed approximately . Maximum speed was . The locomotives used D32 DC generators to supply current to the D37 DC traction motors. For electric operation, the FL9 was capable of using either an
over-running or under-running third rail by means of retractable shoes operated by pneumatic cylinders. For operation into the
Pennsylvania Railroad's
Pennsylvania Station, the FL9 used the
Long Island Rail Road's third rail system. A DC electric compressor provided air for the brake system when the diesel engine was off. To handle the massive amount of electric current available from the third rail, the locomotive's
dynamic braking system operated as a resistor when applying power from a stop or otherwise accelerating. Twenty-eight different steps within the electrical system allowed for the regulation of current supplied to the traction motors based on the locomotive's speed. All units were painted in the bright McGinnis scheme of red-orange, black and white and the
Herbert Matter-designed "NH" logo. FL9s were initially fitted with the
Hancock air whistle instead of standard
air horns.
Production and testing trains featuring the new FL9 locomotives New Haven Railroad president Patrick B. McGinnis initially proposed purchasing 88 FL9s, though the railroad was ultimately unable to afford this quantity. Instead, an initial order was placed for 30 units, numbered 2000 to 2029. The first two members of the class (2000 and 2001) began production in October 1956 and entered service with the New Haven towards the beginning of 1957. They were built with
Blomberg B front trucks, but these were quickly replaced with Flexicoil trucks as the Blomberg trucks lacked room for fitting a contact shoe. They were first sent to the
Harlem Line, at the time operated by the
New York Central Railroad, where the third rail equipment was tested. The tests ended with units 2000 and 2001 both suffering electrical fires, so they were returned to EMD to resolve identified issues. The electrical fires were traced to issues with insulation. Testing also revealed that the contact shoes would sometimes break off of the locomotive when connecting to the third rail. EMD completed its work and returned the units to the railroad approximately six months later, and this time they completed third rail testing without issues. Full delivery of the first 30 units commenced following the satisfactory completion of testing. The initial order of FL9s (2000 to 2029, New Haven Railroad class EDER-5, indicating electric-diesel-electric-road The changes to the design brought the weight of these units down to . ==Operating history==