Few states have more at stake in Warren Buffett’s acquisition of Burlington Northern Santa Fe than Montana. The company owns 90% of the state’s tracks, which are the primarily means for Montana farmers and coal miners to ship their goods across the country.

To get a sense of how the deal is being received in the Big Sky state, Deal Journal reached out to Alan Merrill, president Montana Farmers Union, who can watch Burlington Northern’s grain cars rumble along outside his Great Falls, Mont., office six or seven times a day....