Definition of "single-handed"

It worked through from Swindon with a test train of 16 coaches and the new W.R. dynamometer car, the whole totalling 571 tons; this is one of the heaviest trains ever worked by a single-handed locomotive over the South Devon banks—in fact, it was competently restarted from a test stop on Dainton bank.

1962 April, “Motive power miscellany: Western Region”, in Modern Railways, page 280

"Got those [sc. scars] with a broken bottle, arresting two toughs at once," he said, replacing his cap. "Run them in single-handed and had a set-to in the cell with them on top of it."

1938, Norman Lindsay, Age of Consent, 1st Australian edition, Sydney, N.S.W.: Ure Smith, published 1962, page 21