English: Machynlleth railway bridge A steel structure on very solid stone abutments, typical of the Newtown & Machynlleth Railway. The right-hand blocked up arch originally carried the tramway extension of the Corris Railway to the port of Derwenlas; the extension fell into disuse soon after the standard gauge line was built. There is a distinct hollow in the road as it passes under the bridge, to increase headroom; this is a cause of major problems whenever the Dyfi floods, even by a small amount, sometimes leading to motorists unaware of the depth requiring rescue.