A better "market solution" might be to break up the railroads and undo the last 30 years of consolidation in the industry, then grant a blanket waiver for any environmental permits on projects involving restoration of tracks on abandoned rights-of-way. That would provide some additional rail capacity faster than anything else.
P.S. This is why the U.S. railroad industry remains so heavily regulated even after a heavy dose of deregulation in the 1980s.
The cost paid would not be by the farmers, but the grain grain owners Bunge, Archer Daniels Midland, General mills etc
One aspect that effected me personally was the elimination of Amtrak trains. Back in may we had reservations on an Amtrak train from Seattle to Chicago....... They trains were simply cancelled. We ended up flying.
I think the problem is a great problem for America to have. Scarcity yields growth. It would seem the growth of pipelines will end the pressure on the railroads. You noted rebuilding abandoned trackage that is also growth that would be beneficial.
It will get sorted out and the bottlenecks will be eliminated. There is simply too much $$ involved
The best market solution would be to build pipelines.
Missouri ripped up a couple of their railways to turn them into biking trails.