Britannia Bridge Blaze, 23 May 1970
That was until a few local children unintentionally started a fire that spread throughout the structure and required firefighters from far and wide to tackle the spectacular blaze. As the flames died down and daylight broke it soon became clear Stephenson's rail artery to the island was a melted and charred helix of tar and metal.
This video from the BBC Wales archive is part of a programme from 1978, some eight years after the blaze, called Let's Look at Wales: Crossing the Menai.
Narrated by David Parry Jones, and aimed at a school's audience, the clip shows the blaze and the aftermath. Featuring BBC News footage from the night of the fire, and beginning with a dramatised 999 response, it offers an interesting view of the events on that May night.
During the following decade the bridge was repaired and improved. Rail services resumed from 1972 onwards and by 1980 a road deck was added to what is now the double decker bridge taking traffic along the A55 into and out of Anglesey.
Radio Wales community correspondent Gwenda Parry
speaks to people who remember the Britannia Bridge fire (2006).
Anglesey History: Menai Strait Bridges