Nice video! It certainly is exciting to see all of this action and change happening in the North ave yard.
In regards to your tanker question, I believe it contains corn syrup for the Blommer Chocolate factory.
Up until (roughly) 4 years ago, they used to store 5-6 tanker cars on the spur that snakes toward the Kinzie st. bridge (former Navy Pier line).
Speaking of which...does anyone know why they no longer seem to store cars on that track?