Some of the country's best-known landmarks, including Edinburgh Castle and the Forth Rail Bridge, were plunged into darkness for the event.

BBC: Earth Hour: Thousands of Scots switch off lights

Mr Watanabe worked as a construction foreman on the Forth Rail Bridge.

BBC: NEWS | UK | Scotland | Glasgow, Lanarkshire and West | Rail bridge builder on ?20 notes

Engineering graduate, Kaichi Watanabe, is pictured on the notes alongside an image of the Forth Rail Bridge on which he worked as a foreman.

BBC: NEWS | UK | Scotland | Glasgow, Lanarkshire and West | Rail bridge builder on ?20 notes

Transport Scotland said the freight service would provide a more efficient route for coal from the west of Scotland to Longannet Power Station and reduce rail congestion on the Forth Bridge.

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Thanks to a decade-long renovation project overseen by Network Rail (2002-12) the Forth Bridge is now in the best condition it has ever been in.

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