350 would how many seats on the three cars. They do allow people to stand. This near the halfway point on the route so some will have gotten off at earlier stops.
I’m sorry, I don’t know the answers to your questions.
IIRC correctly each car has 120 seats — don’t remember where I heard that. I do know that I was on a five car train last month and the conductor said we had 600 passengers.
I’ve never riden that line, but I suspect that they took on a lot of people at Burbank who were headed for the Simi Valley and beyond. The short hop people get off at Glendale and Burbank to be replaced with show business (eg Disney) emplyees from Burbank who are long distance commuters.