[blincoln]

The Sounder is a heavy rail train on rails that are shared with other trains (e.g. freight). It runs about 7 times per day in one direction and about 10 times per day in the other. There's no reason to run additional trains on that line, because taking it depends almost entirely on finding an empty space in parking garages that are full by about 6AM.

The Seattle area has a newer, dedicated light rail system (Link) that runs every 5-10 minutes from about 5AM to about 1:00AM. The stations are located much more conveniently and frequently, because they were placed based on where a commuter train should stop, not trying to piggyback on existing freight lines. There still isn't as much parking as there should be, but at least the stations are placed so that more than a tiny handful of people can get there without driving and parking.

[runarberg]

I’m not so sure about that. The North line connects to Edmonds which is a major ferry terminal used by a fairly large number of people on the Kitsap peninsula, Port Townsend etc. plus another ferry terminal on Mukilteo for Whitby island. These are major connections which are unusable in the 4 trains a day frequency (Sounder only runs 2 trips and Amtrak Cascade the other 2; latter does not stop at Mukilteo). The link is good and all that but it won’t reach Everett for another 20 years and it won’t connect with the ferries either.

The South direction is a little better (and is improving even further with more Cascade runs on the horizon) but it is the same story. For example, Pyuallup and Sumner are both decent sized towns wit centrally located station, which won’t get light rail and the 1 line won’t reach Tacoma until 2035 at least. There is also a decent transit center at Lakewood, however I would argue it should probably be better to run the 620 all the way to Tacoma, from where Olympia people could jump onto a Sounder or light rail.