Mercury was the name used by the New York Central Railroad for a family of daytime streamliner passenger trains operating between midwestern cities.

The success of the Mercury led to Dreyfuss getting the commission for the 1938 redesign of the NYC's flagship, the 20th Century Limited, one of the most famous trains in the United States of America.

Here is his description of how the plan developed: The final designs were approved ... but when they were put out for bid prices were so out of line that the project was canceled.

For the Mercury, he achieved a streamlined appearance by covering the exterior pipes, whistles, and other fittings in a smooth "bathtub" cowl.

[17] The Mercury trains also incorporated roller bearings on their axles,[10] which helped them reach their speed limit of 80 miles per hour (130 km/h), but also made them harder to stop.

[19] It has been said that, "As opposed to [some of his] contemporaries, Dreyfuss was not a stylist: he applied common sense and a scientific approach to design problems."

The exterior of locomotive and cars was medium gray with brushed aluminum trim (though there have been incorrectly colorized images of the Mercury in a light blue livery which never existed[citation needed]).

[20] For the Mercury, Dreyfuss, approached the design of the train as an integrated whole, interior and exterior, from the locomotive to the rear observation car.

[21] His primary concern toward that end was to mitigate the rigid uniformity and long, narrow form of the conventional railroad car.

To maximize the view, he lowered the sills in the observation area by 30 cm (12 inches), allowing 1.23 m (four foot) high windows.

In an extra touch, a speedometer was built into the center banquette, a reminder of how the Central was marketing speed with the Mercury.

[23] The original, Dreyfuss-designed Mercury train set comprised nine cars:[25] The cars were modified for Mercury service in New York Central's Beech Grove, Indiana, shops; the first train operated on test runs in June 1936 on a 200-mile (320 km) stretch between Indianapolis and Sheff[26] reaching speeds of 93 miles per hour (150 km/h).

[3][10] The inaugural Mercury trainset was taken on an exhibition tour throughout the New York Central system in late June and early July 1936.

[1][2][3] By September 1936, New York Central found that the new Mercury service did not impact the ridership on other trains it operated between those two cities.

[14] In February 1950, the westbound Detroit-Chicago Mercury was suspended due to coal shortages while the eastbound counterpart remained in service.

The cancellation was the result of an Interstate Commerce Commission order to all railroads still using coal-powered locomotives to reduce services.

Because the trains regularly operated at speeds of 75–80 miles per hour (121–129 km/h), accidents occurred at level crossings along their routes.

[52] In another incident in Ohio in 1938, a truck crossing the track in front of a Mercury train was struck and thrown several hundred feet from the collision site.

[59] The Mercury was also affected by other incidents on the system, such as on July 25, 1957, when a freight train derailed 22 cars at Ceylon in Erie County, Ohio.

The derailment scene was severe enough that New York Central rerouted all of its major passenger trains over a lesser-used branch line to bypass the accident.