This could actually also fall in the In from the cold thread, but I went for the original period of use.
Last week we spent a most enjoyable few days in the Highlands, traipsing beyond in a southwards direction up to Loch Awe. On our journey we drove up and down the B8074 road in Glen Orchy (promising name, that!), and branching across the river Orchy at a place barely recognised by the internet called Eas Urchaidh we saw this:
Am I right in suspecting it's a Bailey Bridge?