It's New Year's Eve and on Sydney's Harbour Bridge the most ambitious ever repair of the Bridge's rail corridor has begun. A massive lightning strike takes out a signal box, bringing trains to a halt.

Back at Central, we meet Nasser, a customer service attendant at Central Station. Nasser is first on the scene when a woman faints onto another person standing on the platform.

At Lidcombe station, a man has tragically taken his own life. Although the human tragedy is overwhelming, rail staff focus on dealing with the immediate impact on passengers and the network.

Sydney is in the grip of one of the worst weather events in decades. Over 48 hours, the city is drenched by over 300 millimetres of rain causing chaos on the rail network. As rain buckets down across Sydney, staff at the Rail Operations Centre are bracing themselves for the worst.

In this episode, we mark the anniversary of Australia's worst train disaster. In 1977, 84 people were killed when a passenger train left the tracks and crashed into an overpass at Granville. The day is marked with a sombre ceremony, but it also serves as a reminder of how much safer the network has become as a result of the lessons learnt that day.