speeder

[spee-der]

noun

a person or thing that speeds.
a driver who exceeds the legal speed limit.
a small self-propelled railroad car powered by a gasoline engine and used by section hands.

Origin of speeder

Middle English word dating back to 1350–1400; see origin at speed, -er¹

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

At a is the slot for receiving the arm from the speeder and from the stop motion.
Modern Machine-Shop Practice, Volumes I and II
Joshua Rose
It is obvious that the speeder can be adjusted while the engine is running.
Modern Machine-Shop Practice, Volumes I and II
Joshua Rose
"Speeder," Ben snapped as he jumped down the steps to the side hatch.
Code Three
Rick Raphael
The speeder has under her care as many machines as her skill can control.
The Woman Who Toils
Mrs. John Van Vorst and Marie Van Vorst
The girl at the speeder next to me had just had her hand mashed to a jelly.
The Woman Who Toils
Mrs. John Van Vorst and Marie Van Vorst

"one who drives fast," 1891, agent noun from speed (v.).