E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
and Crawlers. The four-wheel cabs; called growlers from the surly and discontented manners of their drivers, and crawlers from their slow pace
Taken as a whole, the average drivers of hansom cabs are smart, intelligent men, sober, honest, and hardworking . They have little in common with the obtrusive, surly, besotted drivers of the growlers and crawlers.Nineteenth Century, March, 1893, p. 473