[Update: The Fargo Forum also ran an editorial where the North Coast Hiawatha got a positive mention.]
Amtrak released a study in 2009 saying that it would cost about $1 billion—a hefty sum, though the improvements would be spread across a 2,200-mile route. Of course, since the route closely follows an Interstate highway, there's a strong argument to be made for improved bus service instead (I don't like the argument, but it's certainly a valid one).
Here's a cost breakdown I put together by looking at the report:
|Improvements to new/restored route||$518|
|Improvements to existing Amtrak routes||$101|
|Positive train control (PTC)||$60|
|Purchasing 6 new trainsets||$330|
|Building/restoring 17 stations||$17.6|
|Training 269 workers||$16.8|
About half the cost would go into restoring rails and stations, while nearly a third would be put toward new train equipment. Most of the rest would be put toward improvements to rails already served by the Empire Builder and other Amtrak trains, with a tiny portion left over for training new employees.
The study indicated that the new train would have a 58% farebox recovery ratio, which doesn't sound that good but is actually well above average for Amtrak's long-distance trains. They estimated that it would only be outpaced in financial performance by the specialized Auto Train, the Empire Builder, and the Palmetto.
The North Coast Hiawatha was considered a successor to the former Northern Pacific Railway's North Coast Limited and Mainstreeter routes, with a bit of the Milwaukee Road's Olympian Hiawatha mixed in. Amtrak introduced the train in mid-1971, restoring service to a route which had lost its trains upon the creation of Amtrak on May 1st of that year. It was a normally a thrice-weekly train, sharing parts of its route with a (then-)quad-weekly Empire Builder, though they would sometimes run daily during busy summer and holiday periods.
When the North Coast Hiawatha was discontinued in 1979, the Empire Builder was taken off of its historic routing through Willmar, Morris, and Breckenridge and began serving St. Cloud, Staples, and Detroit Lakes instead (this explains the strange kink in the Empire Builder's route between Fargo and Grand Forks). At about the same time, the Twin Cities train station changed from the Great Northern Depot in Minneapolis to the current Midway station in Saint Paul.
Hopefully the interests of North Dakota, Montana, Idaho, and Washington will soon come into alignment with those of Minnesota and Wisconsin. Here in Minnesota, there's a strong desire to create a "second Empire Builder" running from Chicago up to the Twin Cities and on to Fargo, so a restored North Coast Hiawatha could fulfill that role. The big thing now is to actually commit to building something—it will take 4 to 5 years to start up the train service, mostly due to the time to design and build new equipment and to engineer the infrastructure improvements.