Caption: For my time machine shot, CN M398 exits the Paul M. Tellier International Tunnel in to Sarnia yard. I'm comparing my shot to Bill Thompson's 23 years ago http://www.railpictures.ca/upload/canadian-nationals-st-clair-tunnel-at-sarnia-was-too-small-to-handle-higher-cars-such-as-double-stacks-so-the-decision-was-made-to-bore-a-new-larger-tunnel-a-special-ceremony-was-held-on-septemb . What has changed in 23 years? To handle traffic and to stay in the market, and new tunnel was bored to handle higher cars such as double stack intermodals.