Much of what mook said also goes for Metrolink Riverside line. Before it began, there were many naysayers saying no one would ride it to make the cost worth while. I think it was within a year that the 4 daily trains were packed after the City of Industry stop. And the parking at that station has been expanded 3 times. If UP would only allow it, Metrolink could probably easily fill 2 more round trips per day, plus 2 rounds trips on Saturday. Maybe once all the ACE projects are complete and the triple track between Industry and Pomona stations is in place UP will finally allow it.