Well one of the most striking must've been at Hawick, where Mansfield Road left the A7 adjacent to the Station pub, and passed beneath the platforms which spanned both it and the river Teviot on the viaduct of that name.
A dozen miles or so away at the rural market town of Newton St Boswells, the A68 burrowed right under the heart of this classic junction station, whose component parts make for a compelling model.