TSW is lacking metro and light rail routes, a vast majority of the routes that provide a similar service would be more regional/commuter rail style. I think a good route to get on top of that would be Sound Transit's new 2 Line service. It's a good mix of everything, it has sections that could be considered light metro, and some sections that are mainly proper light rail with grade crossings and tight bends. The route is about 33 miles starting in Lynnwood, snaking through Northgate, the University of Washington, Downtown Seattle, Mercer Island, Bellevue and the Microsoft main campus before terminating in Downtown Redmond. The total runtime should be just a bit over an hour for the full route. The route comprises sections that are elevated, at-grade, tunneled (both cut and cover and bored). The rolling stock is very simplistic, being comprised of just two types, Kinkisharyo LRVs and Siemens S700s, which aren't compatible with each other (so no randomization of rolling stock required for the same train), and both types should run a 4 car/train consist. The frequency is roughly every 8 minutes, when you add 1 Line trains (which interline between Lynnwood and Chinatown/ID station) which also run 8 minutes, the core section runs 4 minute frequencies which is really low for a manually operated system. One really interesting part of this route is that it will be the first light rail system to run on a floating bridge. While it is understandable that this would not be simulated in, it would still be really cool to run over this bridge. In addition, this route runs through the old Seattle Transit Tunnel, meaning that for some of the portions the tracks are embedded in a paved surface but has no road vehicles running through it (they used to have buses, but they were moved onto the street above to improve link's reliability). While the route hasn't opened yet (and I understand if they feel like waiting for the route to fully open), the route has finished construction and testing is underway which means no major changes will be made between now and the projected opening early next year, I feel it would be awesome to have the route not long after it opens.
