Investigations after NSW boy hit by train

AAP

The final moments of an 11-year-old autistic boy, who ran away from his carer and was struck by a train in Sydney, is the subject of multiple investigations.

NSW Police mounted a large search involving the dog unit and Polair after he ran away at Oatley shops after 7pm on Sunday.

The boy, who was non-verbal, had been staying at a respite centre.

He was found dead at Oatley train station about two hours after disappearing.

Civic Disability Services Limited confirmed the boy was in its care at a short-term accommodation facility when the incident happened.

They have launched an investigation and are co-operating with the police detectives who are piecing together how the tragedy unfolded.

Online the Oatley community reacted with grief and shock.

"As a father of a child with Autism, this sent shivers down my spine," one man said.

"It's the worst fear we continue to live with."