1. Episode 1

In the first episode, it’s the start of the Summer, and the Metro staff brace themselves for one of the busiest days of the year. The Spice Girls are in town as part of their comeback world tour, meaning 50,000 fans from far and wide will be descending on Sunderland, putting additional pressure on the Metro’s already stretched resources.

3. Episode 3

In the third episode, the Metro's ageing fleet comes under pressure when a train breaks down in a tunnel near its busiest station. Meanwhile, track inspection supervisor Wayne has his work cut out repairing decaying sleepers which, if not quickly replaced, could cause a train derailment. And customer service manager Alan has to shelve his plans for a quiet evening after he's called in to deal with an outbreak of anti-social behaviour on the Metro.

4. Episode 4

All hands are on deck as the metro system prepares for the busiest day of the year - the Great North Run. This year, a new and untested station in South Shields is at the centre of things. One of the event's regular runners prepares for a personal return to the course, as he runs in tribute to a friend.