British Rail's East Coast main line is a railway in the throes of change. From London to Edinburgh the overhead wires are going up, and the new high-speed electric trains are being tested. Today's Railwatch looks ahead to the evolving railway, and talks to the people who are working on tomorrow's technology.

They used to be passengers; now they're called customers: a constant stream of people across the concourse, onto the platforms and away by train. With them goes their luggage, parcels and post, to destinations near and far assuming all goes well. On a typical weekday, Railwatch looks behind the scenes at a big city station in Leeds.

Twenty-four hours a day, the 'merry-go-rounds' - coal trains that never stop - run from colliery to power station. Elsewhere on the railway other commodities are being moved, often in whole train loads. And in the small hours of the morning, the passenger train-sets are being prepared for another day's work. Railwatch reports on the railway the public never sees.

Edinburgh Inter-City 125 heads north, behind the scenes its progress is monitored and controlled by many an unseen hand. From signalling centres, operations centres and Eastern Region Control in York, Railwatch reports on the men who do run the railway.

All year round, 24 hours a day, British Rail is part of the nation's life blood. It is used, abused, tolerated, criticised, appreciated and even sometimes praised by all of us at some time or other. With a turnover exceeding £2,000 million a year, and more than 130,000 staff, it is one of the country's major industries. Railwatch is live from York, historic railway city and headquarters of BR's Eastern Region, the midpoint of the prestigious East Coast main line that links London with the north of England and Edinburgh. Every day this week, the programme goes behind the scenes to find out by whom and how the network is run.