Caption: It's 17:09 on the coldest day of the winter yet and Union Pearson Express 4091 is knocking down the advance to Pearson on the west track of the Pearson Sub. 1010, 3004 and 1002 will make 6 more roundtrips before returning to either Don or Willowbrook Yard or the TMC, while the passengers onboard may find themselves thousands of miles away in warmer weather by the time that happens. Shadowed by the guideway and value park garage, traffic comes and goes. By the time this consist returns to the airport 75 minutes later, it is possible that passengers from the landing plane in the background will have made it through customs and baggage claim, ready to board the UP Express for a trip into the city.