Melbourne commuters can expect serious delays after a chaotic day on the city’s train network.

At 7pm, major delays still were being reported for the Cranbourne and Pakenham lines after a string of dramas that included a car straying onto a level crossing.

Minor delays were also being experienced along the Cragieburn, Sandringham, Upfield, Werribee and Williamstown lines.

The day of drama began when a woman was hit by a train at West Richmond station just before 1pm.

An Ambulance Victoria spokesman said the woman, in her late teens, was "dragged some distance" by the train and suffered serious chest and abdominal injuries.