A year 7 student is in a serious but stable condition in hospital after he was trapped under a train in Melbourne on Monday afternoon for up to an hour.

Firefighters and paramedics were called to North Melbourne Railway Station about 4pm to rescue the boy, who attends St Aloysius College in North Melbourne.

The ABC was told he had been on platform 6 at the station when he was hit and trapped under a carriage.

A Fire Rescue Victoria spokesperson said the schoolboy appeared to have been caught by his leg, suffering serious injuries.

A number of train services were cancelled while the rescue took place.  (ABC News: Alexandra Alvaro)

He said firefighters used hydraulic jacks to lift the train off the tracks to free him, with the rescue taking up to an hour.

The boy was rushed to the Royal Children’s Hospital, which is not far from the station, and was in a critical condition on Monday night.

This morning, the Royal Children’s Hospital said the boy’s condition was serious but stable.

St Aloysius College principal Mary Farah wrote to the school community on Monday to provide an update.

“Our immediate priority is providing support to the family and ensuring our community is kept informed as reliable information becomes available,” she said.

“In times of such sudden and distressing news, the strength of our college family is more important than ever.

“I know that your thoughts and compassion will be with the student and their family as they face this incredibly difficult time.”

Earlier, aerial footage showed workers crouched between two carriages while others assisted from the platform where a stretcher could be seen nearby.

There was a large scale emergency response including police and firefighters. (ABC News)

Paramedic Alex Hemsley described the scene as upsetting for emergency responders.

“We transported the young person quickly under emergency conditions, lights and sirens conditions, with a pre-notification to the Royal Children’s Hospital with regards to their injuries,” she said.

“Although we are all trained to do this job, it was a very traumatic scene for all involved.”

She said support would be offered to all who were on scene.

Paramedic Alex Hemsley has described the incident as traumatic. (ABC News)

Ms Hemsley said at one stage, there were up to eight paramedics helping the boy, including advanced life support and mobile intensive care teams, as well as the firefighters working on releasing him.

“They did everything as quickly as they could have done, provided the highest level care to this young person on potentially one of the most traumatic days of their lives.”

The incident happened as Melbourne’s rail network geared up for the afternoon peak.

A number of services on the Williamstown and Werribee lines were cancelled while the rescue operation took place.