The UP pool train operated by way of the Steel Bridge and Albina Yard until the 50's when Albina Yard was extensively rebuilt and any mainline track was removed. It was at this time that the UP negotiated trackage rights over the SP&S/NP/GN mainline north out of Union Station through Willbridge Yard and on to Vancouver.

The large UP trains occured in 1962 when the Seattle World's Fair was taking place. There would be the regular train that would depart on time and then a second section which would leave once the City of Portland and the Cascade had arrived. Normally, all of the cars would be assembled into one return train that departed Seattle in the evening. I rode it once when it had 6 E-units and was 28 cars long. In later years the UP would use the City of Portland set, basically minus the sleepers, for their train to Seattle.