The original ballot measure promised the equivalent of an interurban line with speeds in the 60 range (high end of light rail), which are necessary to maintain any kind of competitive schedule. Can't do that on Class 3 track with no signal system. Add to the track/signal needs the cost of building stations to Federal Transit and ADA standards (i.e. not just a patch of asphalt next to the tracks), upgrading grade crossing protection for the higher speeds, fixing assorted tunnels and bridges that an occasional 20-30mph freight train doesn't have to worry about, buying cars that can do the speed and meet the various transit standards, and other odds/ends, and you have a large chunk of change.

If you try to go slower, the line isn't competitive with even local (all stops) bus service. If you don't do the upgrades, it's maybe a dinner train run and that's it for passengers. Of course, remember that the olde NWP didn't run commuter service north of San Rafael; the couple of trains on the line where SMART would be were (even by light rail standards) pretty slow.

Of course, if the opponents succeed in their attempt (see recent Trainnews) to repeal the SMART measure, it's all over anyway. Would the tracks revert to NCRA if SMART goes away?