They tell the passing train to speed up and the other train tells them "they are notching up" meaning they are adding more throttle or power to the traction motors.

These two, the locomotive engineer and conductor, will probably lose their jobs or face severe discipline from CN for using their cell phones while on duty and posting this to social media.

I can't imagine how terrified they must have been, you can hear it in the engineers voice when he talks to the other train crew. Apparently the train had dangerous/flammable cars close to the locomotives and that made it even more terrifying.

They both got out of there without injury and nothing happened to the train.

I though they were waiting on workers at the other end of the train. Dropping a car or connecting cars. Freight trains can be very long