ALCO Century Series locomotives

During the 1950s, EMD had become the major player in the North American diesel locomotive market, with Alco relegated to second place.

By 1956 General Electric had launched its first Universal Series road locomotives primarily as export units.

[1] Faced with this market situation, Alco in 1962 completely redesigned its road locomotive line, creating what would become the Century Series.

The locomotives were designed to equal and surpass competitors' products in terms of both features and performance.

[2][3] During speeches at the event, Alco executives promoted the new locomotives' reduced operating costs, a major effort in the design of the machines.

Combined with unit reduction through higher powered locomotives, as well as liberal trade-in terms, Alco claimed operating cost could be reduced as much as 44%.

A total of 131 units were built, including 22 passenger models for the Long Island Rail Road in 1963, supplemented in 1968 by an additional order of eight more with Alco's Hi-Ad trucks.

[4] The C628 was intended as a replacement for the C624, announced at the Chicago launch event, but never produced due to being made rapidly obsolete by improvements in engine technology.

[4] The C855 was launched in 1964 in response to a request from Union Pacific for a dual engine unit to replace up to ten first-generation locomotives.

It was launched in 1966 as the latest update of B-B locomotives, and introduced Alco's new high-adhesion truck, offered as an option on the C630, but standard on the C430.

The C624 was one of the original models announced at the launch event, but never went into production, its design having been eclipsed by rapid advances in engine technology.

The C636P was a dual service design, and the C636F was Alco's response to a request by the Santa Fe Railroad for a cowled locomotive in both cab and booster form.