1944 May and June, “Notes and News: Express Travel on Slow Lines”, in Railway Magazine, page 184:
[...] Mr. M. N. Rollason points out that on four-track lines on which the fast lines, in the centre, are flanked by the slow lines, and running at speed is permissible on all four, the traveller can enjoy some quite exciting experiences when trains are doing a "neck-and-neck" on adjacent lines.
2023 January 11, Richard Foster, “British Rail's weirdest railways...: Wisbech & Upwell Tramway”, in RAIL, number 974, page 46:
It was a rural railway that served the fertile Fens of Cambridgeshire and Norfolk. But because it flanked public roads and was unfenced (to save costs), it was deemed a tramway and its locomotives had to be fitted with a cowcatcher.
(intransitive) To be placed to the side(s) of something (usually in terms of two objects, one on each side).
Cautiously I approached the flank of the cliffs, where they terminated in an abrupt escarpment as though some all powerful hand had broken off a great section of rock and set it upon the surface of the earth.
1960 January, G. Freeman Allen, “"Condor"—British Railways' fastest freight train”, in Trains Illustrated, page 48:
Ahead the flanks of the Pennines gleamed faintly in the moonlight, looking as though they themselves were part of some dry and deserted lunar landscape.
(US,nautical, of speed)Maximum. Historically faster than full speed (the most a vessel can sustain without excessive engine wear or risk of damage), now frequently used interchangeably. Typically used in an emergency or during an attack.