A train ride is 8+ hours.
12, actually. But it's worth it once, especially if you enjoy riding trains.
From out of state, I didn't think the actual filed fares for [out-of-state]-FAI city pairs were much more than [out-of-state]-ANC. If they are, though, a one- or two-day, one-way, rental car ANC-FAI might be a better deal than both plane and train tickets, even with high summer rental car rates.