I asked Doyle this question when 4449 went to national train day at union station for the return trip to Brooklyn yard at that time, the curves leading into Albina yard and on the north leg of the wye are very tight and since you would have to back towards Albina yard into those tight curves to clear the approach signals to the wye..it is not a chance he wanted to take with the engine. This is also why when 4449 double headed with UP 844 back in 2007, 4449 went around via union station route then backed down to Kenton on the UP to meet 844 for the trip to Tacoma verses going through the Albina yard and through the tunnel to meet 844. If you notice.. All visits by UP 844 to Portland also in the past stayed over at Albina yard for this same reason.