Green’s Dictionary of Slang

trig n.3

[17C SE trig, to go in a hurry]

a trot, a hurried walk, a trip.

[[UK]Etherege Man of Mode III iii: There’s many of my own sex with that Holborn equipage trig to Grey’s-Inn Walks].
Holland Cheshire Gloss. 368: He’s allus uppo th’ trig (always in a hurry) .