The Crawler-Transporter 2, the largest and heaviest self-propelled ground vehicle on the planet, is stationed at NASA’s Kennedy Space Center in Florida.
The largest and heaviest self-propelled ground vehicle on the planet, per Guinness, sits at NASA’s Kennedy Space Center in Florida. Creatively dubbed Crawler-Transporter 2, this monstrosity is the size of a baseball diamond, and while it’s over 50 years old, it will be expected to continue to dutifully serve the national space program for decades to come. NASA says it has a max speed of just 2 miles per hour, slower when laden with a launch payload. Even at those slow speeds, the CT-2 has logged over 2,300 miles on its odometer, powered by a pair of massive ALCO 251C V16 diesel engines making a combined 5,500 horsepower.
CT-2 has been upgraded to Super Crawler specifications so it can handle the extra weight of Space Launch System rockets ahead of the Artemis project that means to return humans to the moon (as well as of huge budget cuts Congress might not make). While the machine itself weighs a full 6.6 million pounds, an SLS rocket is an additional 5.8 million pounds. To shove around that much weight, the two diesel engines work in conjunction with 16 electric traction motors with a combined 6,000 horsepower and instantly variable torque. When it was built in 1965, the CT-2 required the equivalent of 20 Hi-Po V8 Mustangs to move around, but in 2026 this machine could theoretically be moved by the horsepower equivalent of just four Lucid Air Sapphires.
So did ALCO build these engines specifically for the space program to use as a ground transporter diesel generator? No, of course not. ALCO is short for American Locomotive Company, and these engines kicked off production a decade earlier in Schenectady, New York. The original use, the intended use, of the ALCO 251C was powering trains across the American, Mexican, and Australian countryside.