Weighing in at more than
400,000 pounds and with a length in excess of 80 feet and massive
4,300 horsepower tractive effort, the SD90/43MAC is one of the
heaviest, longest, and most powerful single diesel locomotives
in the world. To date, there have been three production "versions"
of the SD90MAC. The SD90/43MAC was originally designed with
a 6,000hp engine in mind, but was fitted with a smaller and
more reliable 4,300hp engine that ended up being kept that way
by most railroads, even though the option to upgrade to the
higher horsepower engine was offered at a later date.