BR reveals the secrets behind its sandwiches

The much maligned British Rail sandwich, the soggy, curly, staple diet of stand-up comics for more than half a century, was the subject of meticulous culinary precision, an exhibition revealed yesterday.

Employees were told by senior management to stack at least a third of the sandwich filling on the centre of the bread to make it look attractive when cut in half diagonally.

Staff were also under precise orders on how much they put between the slices, according to a 30-year-old document unearthed from the collection of British Rail papers in the archives of the National Railway Museum at York.

Instructions issued in November 1971 by Bill Currie, BR's director of rail catering at the time, as part of an attempt to make its food "the best on the track", stated that sandwiches should contain three-quarters of an ounce of cheese, two-thirds of an ounce of luncheon meat, cress or sardine and no more than a quarter ounce of gherkin.

Despite the sandwich's reputation, BR sold eight million in 1993, its last year as a public company. By then even some Parisian bakeries were said to be receiving courses on how to make le sandwich out of soft, spongy bread.

The sandwich directive is part of A Moving Story – an exhibition at the York museum on the story of BR from nationalisation in 1948 to privatisation by the Thatcher government nearly half a century later.

The exhibits include some of the most-loved trains and tells the stories of people who worked for BR, including the caterer Myra Tuddenham of Newcastle upon Tyne, who insisted the sandwiches were "terrible" because the glass domes in refreshment rooms made them curl.