Thanks for all of your comments and inputs, ya'll. sorry I'm taking so long to get back to you. The conductor was the assistant conductor that we've seen run 507 lots of times. She was standing the doorway of business class as the train sat there for a while. I can confirm she said "I think so" to the engineer. I went back and watched the tape. There is no way she though they were part out our video group, as we were at least 100 feet away from the stranded passengers. The passengers said they were headed to Eugene from Oregon City and would now have to wait until morning. We all tried to alert the crew, but we (the filming group) were too far away from the train, up top near the station building, and the two ladies missing the train ran with it for a while waving their arms - but no luck. I still believe amtrak should have opened a for in coach seating, or at least done a better job of looking for passengers needing to board. "I think so" should never be a confirmed way of communicating.
Thanks for your inputs
-Cole
PS: I'm "AmtrakPNW" on YouTube, and my recent Cascades Compilation has the exchange in it. You can hear the conversation on the scanner, as well as a few faint shrieks and please from the passengers getting left there. Towards the end.