I'd be more interested in improving the bus network if there were some dignified stations to wait at. For Eau Claire, some buses make it to the University of Wisconsin campus in town, but many just stop at this McDonald's
, which is close to an I-94 off-ramp, but is seven miles from the central business district.
I tend to think the Eau Claire line would have ridership in the 400,000 range -- that's about 50% of the estimates for the Northern Lights Express line to Duluth, which is a somewhat larger region (280,000 people vs. 210,000) and more touristy, but farther away (150 miles instead of 100). The historic projections have been that the Duluth line would run right around break-even in terms of operating cost vs. ticket revenue, but who the hell knows since we haven't built it or anything else like it.
I stare at buses and aircraft and don't really see what's fundamentally different about operating them versus trains. The Eau Claire airport only handles around 35,000 passengers a year, and the per-seat cost of an aircraft is about as much as a house. Train vehicles cost about a tenth as much per seat. Trains obviously run on rails, but aircraft need airports, and there's the invisible infrastructure of air traffic control which costs a lot to operate. (And yes, I know that's an even smaller amount of traffic -- train fares would be cheaper than the airfare by a pretty good margin, which would attract people, and it would be connecting them to closer destinations which they're more likely to visit than whatever long-distance trek the fliers were probably taking via O'Hare).
Building and operating a train service mostly seems to come down to how dickish the freight railroads are about asking for track improvements they don't really need in order to scare people away from running passenger trains, and/or charging an arm and a leg for track access when passenger trains don't really do much damage to the rails.
Here's a document with maintenance cost estimates on passenger rail lines
. I'd guess that this line does about 10 million gross tons per year in freight service (around 7,000 tons per train), which puts track maintenance cost in the range of $0.77 per mile for passenger. Considering that rail fares tend to land in the range of $0.15 to $0.30 per mile, it wouldn't take many passengers to cover the cost of keeping the tracks in good order. The big hurdle is just upgrading what currently exists back to a standard that people could reasonably use.