On sight

I recognized him on sight.

"Permissive" working allows more than one train to be in a block section at one time but trains must be run at low speed in order to stop on sight behind the train in front. Such working is often authorised to allow freight trains to "bunch" together to await a path through a bottleneck instead of being strung out over several block sections, as would be necessary if absolute working were in force.

Somewhat unsurprisingly, unleashing the most powerful navy on the planet with carte blanche to exterminate slavers on sight saw a dramatic and sudden collapse in slaver numbers in the late 1840s and early 1850s.

He dismissed the idea on sight.

If he keeps talking crap about me, its on sight.