As noted, the schedule of test runs can change. Today's did. The test ended at Vancouver, WA, and is making the return trip from there. Because the schedule is off, there are no times to share for the northbound run. Catch it in the wild if you can.
Thursdays offer more chances to see the new Amtrak Cascades train. Departs Seattle 6:20 am-Arrives in Portland 9:42 am. Departs Portland 10:50 am and reaches Seattle near 3 pm. These are training runs so the test schedule is subject to change. Photo courtesy of Nathan Bofto.