Wiktionary
n. A rocket-propelled vehicle constrained to run on a rail used for experimental purposes.
Wikipedia
A rocket sled is a test platform that slides along a set of rails, propelled by rockets.
As its name implies, a rocket sled does not use wheels. Instead, it has sliding pads, called "slippers", which are curved around the head of the rails to prevent the sled from flying off the track. The rail cross-section profile is that of a Vignoles rail, commonly used for railroads.
A rocket sled holds the land-based speed record for a vehicle, at Mach 8.5.
Usage examples of "rocket sled".
It had yawned wide open again, and the book rushed toward its climax the way the best ones did, as if on a rocket sled.
You don't even have any limbs on that-you're just neural ganglia strapped into a rocket sled.
You don't even have any limbs on thatyou're just neural ganglia strapped into a rocket sled.
Holy God, boss, I feel like someone put my brain on a damn rocket sled.