One of the two LWT12 units preserved (including its original set of coaches).

The EMD (Electro Motive Division) LWT12 is a type of four-axle, 12-cylinder, 1,200hp type of streamlined diesel locomotive built from 1955 to 1958 by the Electro Motive Division of General Motors (GM) for the company's short-lived, experimental "Aerotrain" high-speed train project.

Only 3 units (including matching trainsets) were built, and only two are preserved (minus a 5/8 scale replica; the "Zooliner", currently operating at the Washington Park and Zoo Railway in Portland, Oregon's Washington Park). Number 3 currently resides at the Museum of Transportation in St. Louis, Missouri, while Number 2 resides in Green Bay, Wisconsin at the National Railroad Museum.


Originally meant to promote and increase passenger train travel and ridership to keep up with the rapid airline and automobile travel increases of the time, GM intended on outselling the competition by promoting its uniquely-designed "Aerotrain" express service intended for use across multiple train routes from coast-to-coast under their short-lived "lightweight with a heavyweight future" program. Although the overall design proved to be popular amongst passengers, employees, spectators, and the rest of the general public, the Aerotrain service didn't sell well or generate enough popularity to earn a decent revenue with ticket sales from annual ridership, and service ended by 1966.

Although essentially an SW1200 dressed in a "prom dress" (a pun or play on words on how fancy the streamlining was for such a heavy-weight, "down-and-dirty" type of diesel locomotive), the LWT12 was part of a short-lived attempt at designing a high-speed DMU (diesel multiple unit) trainset capable of traveling at speeds of 90 to about 105mph. Mechanically, the LWT12 and subsequent coaches (modified from GM Truck & Coach Division 40-seat intercity highway bus bodies) performed rather poorly, for the locomotive was vastly underpowered due to its otherwise heavy streamlining and poor interior design which rendered routine maintenance difficult. The coaches on the otherhand, were built with suspended axles (reminiscent of today's Talgo trainsets) which were intended to give a smooth, comfortable ride; but did the complete opposite.


The three Aerotrain sets were owned, leased, and/or operated amongst numerous Class 1 railroads throughout the United States, such as:

  • Pennsylvania Railroad as the "Pennsy Aerotrain", which was the first built and delivered, and ran between New York City and Pittsburg, PA.
  • New York Central acquired the second train as a demonstrator in response or conjunction to the Pullman "X-Train" or "Xplorer" trainset in which they acquired prior.
  • Atchison, Topeka, And Santa Fe (ATSF; Santa Fe) acquired the latter sets for use on their "San Diegan" train between Los Angeles and San Diego, CA. Its use ended for the trains had to be turned after each trip and required helper units up the Sorrento Grade north of San Diego.
  • Union Pacific (UP) briefly tested a set for use on its "City of Las Vegas" train, but eventually sold it to the Chicago, Rock Island And Pacific Railroad (while acquiring the other two) for commuter service in Chicago.
  • Chicago, Rock Island And Pacific (Rock Island; RI; CRIP) operated the previous two while acquiring the third built to be utilized for commuter service until 1966.



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