It is the height of summer and as the temperature soars, tensions rise as commuters face delays caused by a broken down train outside central London. In severe heat, the tracks can expand and with fears of them buckling, it falls to the team in Network Rail's Swindon control centre to manage the situation, and they are left with little choice but to issue speed restrictions of just 5mph.
The staff step back in time when they venture down into tunnels under the station to carry out fire safety checks, and it is the start of the Bank Holiday getaway for thousands of commuters. Jennie, Great Western Railway's new customer ambassador, manages to seat a troupe of young cheerleaders all together, but faces a much bigger challenge when fire alarms go off during rush hour.
Signal problems lead to a restricted service during rush hour, which causes severe congestion at the station and the same equipment causes more grief 24 hours later - leading to the complete suspension of the line. Jonny and his team of engineers are replacing a 60ft section of rail as one of the clamps holding it in place has weakened, but they have just four hours to complete the complex task before the morning rush begins.
Paddington's managers debate whether to close the station completely due to storms, something that has happened on very few occasions since world war II. There is excitement among staff as Prince Harry and Meghan Markle board a train to Cardiff.
Lost power between Didcot and Paddington causes problems. A truck strikes a railway bridge. A woman has a cardiac arrest at a ticket barrier. In the wake of the Salisbury nerve agent scare, containers of a unknown chemical found on board a train.
British Transport Police chase down a mysterious trespasser known as Spiderman. The Great Western Railway's top brass holds a naming ceremony for a new electric train, but the new route requires demolishing a 120-year-old footbridge in only 72 hours.
A fatality on the line at Slough station means closing the station and the line, leading to a standstill. A Thai princess and her entourage are eager for a tour of the station. Thieves have robbed a scrap yard and used the railway track to get away.
At Paddington, the early morning service from Swansea breaks down and causes major disruption during the morning rush hour. Meanwhile, the staff face further challenges with a string of medical emergencies at the station and sabotage on the tracks.
A track circuit failure closes a platform which is used by high-speed trains, British Transport Police are out in force as rival Oxford and Millwall fans use the network, and a young man is seen on CCTV walking close to the edge of the platform.
As Storm Eleanor strikes, a fly-away plastic bag causes a power outage trapping three trains, and in Hungerford a falling tree hits a Penzance bound service.
The trains to the Cheltenham Races are standing room only, even in first class. Potential flooding at Cowley Bridge could cut off all of Devon from the networ. Emma uses thermal imaging to inspect the lines for defects from a helicopter.
The big Easter getaway brings huge numbers of passengers and problems to the station, a team of 500 carry out a vast re-sigalling project, and Revenue Officer Moses keeps an eye open for anyone attempting to sneak through the barriers.
A major wedding approaches, and rail staff have their work cut out to get the station ready.
An intruder puts his life at risk by running along the tracks. Meanwhile, engineers work around the clock to install new cables at Newbury as part of the multi-million pound project. Also, ticket machine refurbishments do not go to plan.
A heatwave hits hard, causing havoc with signalling equipment at Didcot.
The British Transport Police mount a operation to stop criminals who are running drugs out of the capital. Also, a crack has been discovered on a rail joint at Acton East and at Paddington, a passenger has fallen between the train and the platform.
A nasty surprise awaits engineers as they discover rotten wooden sleepers that disintegrate under foot. Even veteran train staff are shocked by the reason the 15:00 to Bristol has come to a halt - A driver tried to start the train from the wrong end.
Weekend works at Acton have overrun, tying up the fast line out of Paddington. Also, a lorry rips the safty barrier off a level crossing as it rubs the lighrs, nd the flying banana trails the rails for defects.
Huge delays occur after a man is hit by a train at Southall, and more chaos occurs when the power out on track is accidentally switched off. Meanwhile, hundreds of train enthusiasts descend on Paddington to see the world famous Flying Scotsman.
Swindon control finds an intoxicated man running on the tracks, forcing them to shut the line. Engineers at Cowley Bridge near Exeter insert 24 huge culverts to ease flooding. In Paddington, a drink addled dentist thinks he left his bag on a train.
The bank holiday works schedule is disrupted when a trespassers is o the line outside of London, forcing the cancellation of all trains. However, the shutdown allows the engineers onto the track to renew large sections of the rail infrastructure.
Swindon control jump into action when an unexpected WWII bomb is found near the line in Teignmouth, transport police seek a world with a man who jumped onto the track to get something, and team leader Matyn reveals the cost of cleaning up graffiti.
A year long look at the staff working hard at Paddington railway station – one of Britain's busiest.
A heat wave causes a points failure near Didcot. A young man is seen retrieving his belongings from the track.
The arrival of autumn brings new challenges, from a leaking roof to storms and an unexploded WWII bomb.
While the lines are quiet over Christmas a mega-crane is brought in to replace track near Oxford.