HS2 may be the most exciting news in the world of railways, but by the time it is built the existing system may well have to cope with twice the number of passengers it does today. The team look at the many measures engineers are taking to ensure Britain's ageing rail system stays on track.

Liz Bonnin looks at how signals may disappear from the trackside and how hearing impairment could be one of the biggest killers on the railway lines. Meanwhile, Maggie Philbin looks at how a train travelling at 125 mph is set to revolutionise trackside maintenance. Show less