09/18/2013 08:22 EDT | Updated 11/18/2013 05:12 EST

Via train-bus crash dispatch audio: 'Upgrade this to a mass casualty'

Dramatic audio has emerged of an emergency dispatcher communicating with a first responder at the scene of the crash between an Ottawa transit bus and a Via passenger train.

“We’re receiving lot of calls for this one,” one dispatcher says, as she instructs an emergency responder to go to the scene of the crash.

“Any idea how many people on board?” an emergency responder asks.

“It’s a double-decker bus and we keep getting information,” the dispatcher responds.

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Later, one first responder describes the scene.

“We have a double-decker bus, front end of the bus has significant damage, multiple patients on the ground,” he says.

“Upgrade this to a mass casualty, we have one, two … we have about six code blacks, I have at least three or four code fours on the ground. As stated we have a two-storey bus – front end of the bus is missing."

The front end of the bus was sheared off in the collision, and five people were pronounced dead at the scene, including the driver. One bus passenger died later in hospital from injuries.