This was the event that ended onboard checks: https://en.wikipedia.org/wiki/2013_Via_Rail_Canada_terrorism_plotYes, you walk your bags through Customs which is at one end of the station. Once cleared you go outside and circle around to the center of the station and wait inside for about an hour or so before re-boarding. Onboard Customs was in place until a few years ago. Presumably, the introduction of a baggage scanner in the station is the reason they now make everyone leave the train.