Some further background is linked below. To quote the first one:
"Use of the tracks held steady in the 1990s and surged following the fires of 2000 when log hauls drove the traffic count on the line up to 1,000 cars per year. By 2003, however, the traffic had slowed and the track was washed out by floods between Hamilton and Darby and not repaired. Reduced traffic continued between Missoula and Hamilton until June of 2011 when it was closed due to another flood event."
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bitterrootstar.com]
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ravallirepublic.com]
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spellerweb.net]