So for lines with colleges: Friday and Sunday service. I can tell you, though, that places that have a national draw, such as Notre Dame, do not empty out such that a state university might.
Without turning this topic into a "my School's better than your School", let us note that college represents a market which can generate significant "downstream" traffic.
It seems that the "Millennial" generation (and even isn't there a newer one for those born post-9/11 that are now matriculating?) is not as interested in owning an auto as previous ones, such as my "Silent". They gravitate on graduation to cities (as distinct from me who has never lived in one), again without owning an auto where the only option is to "gutter park" it (would you ever catch me "gutter parking" MY car?). They will likely stay there even after saying "I do", and only leave when "little ones", and an SUV, are in the picture.
That represents a rail travel market of long term riders, if Amtrak and it's Local sponsors "do it right". It would behoove them not to provide service to the college market that once had a Fraternity Brother of mine remark upon seeing an IC train, "this looks something out of Dr. Zhivago".