As Calgary police continue to investigate an attempted sexual assault in the northwest Tuesday night, transit officials are singing the praises of a driver who is being credited for interrupting the assault and helping the victim.

It happened around 10:45 p.m. as a woman was getting off a bus near the intersection of Sandstone Drive and Berkshire Boulevard N.W.

The man forced her to the ground and attempted to sexually assault her, police say.

It was at this time that bus driver Amandeep Hunjan arrived.

"The girl came towards me crying. I asked, 'Do you need any help?' She said yes," Hunjan told CBC News.

Bus driver Amandeep Hunjan pulled into this northwest Calgary bus terminal at 10:45 p.m. Tuesday. (Google Earth)

He called his dispatcher who called police and an ambulance.

Hunjan brought the woman onto the bus, gave her water and comforted her until police arrived.

His boss says Hunjan did exactly what he should have done.

"It was clear that she had been attacked by the male, and if it weren't for the operator arriving when he did, we can only predict that it could have been much worse for her," said Brian Whitelaw, head of safety at Calgary Transit.

Investigators believe it was a random attack.

The suspect is white, between 18 and 20 years old, and about five feet ten inches tall with a medium build.

He was wearing a black baseball cap, a grey hooded sweatshirt and blue jeans.

Anyone with information about this attack is asked to call police or contact Crime Stoppers.