as Rich states, that is 1:1 MPH.
do a search for Hot Rod July issue slot drag and one of the top links will be to the article.
Dave Nap has been around a very long time and is well known in the 1/24 slot drag racing ranks.
some 12 or so years ago Bill Iane of Long Island made documented passes in excess of 150 MPH and ET range low 0.4s to high 0.3s on 55 foot Drag Trax timed formica track at about 16 volts.
it doesn't mention track type, timing system or voltage in the article however.
also, back then no one in that scale was using neo magnets, cobalt segmented magnets were trick then.
sadly, there are few and far between 1/24 drag tracks in the northeast now.