mile a minute

mile a minute (plural miles a minute)

1. A rate of sixty miles per hour.
   • 1961 October, “The winter timetables of British Railways: Southern Region”, in Trains Illustrated, page 593:

     The new Waterloo-Exeter times of the S.R. flyer are 2hr 58min down and 1min more up, in less than 3hr, that is to say, in both directions, with the help of four runs timed at over a mile a minute.

2. (informal, as a phrase) Very quickly.

• mile-a-minute

• “a mile a minute” in Lexico, Dictionary.com; Oxford University Press.