When you drive into Swansea on the M4 via junction 44 or 45, you'll drive under a fair number of bridges and flyovers. From underneath, it's hard to actually see what they are - but you might've noticed one which no cars or trains ever cross.
Between the two junctions there's a concrete bridge which, from below, looks slightly worn but otherwise inconspicuous. But one motorway fanatic took it upon himself to clamber through the trees to see what it was all about - and found an abandoned railway running across it.
In one video, covering some of the M4's quirkiest roundabouts and slip roads, Auto Shenanigans host Jon discovers a bridge heading over the M4 that seems to go nowhere. Dense trees and bushes cover the path on either side, and the bridge can be seen from both the M4 and nearby Ynysallan Road.
