Union Pacific ( UNP) weighs in as the largest railroad in North America, with more than 32,000 miles of track that links 23 states, Canada, and Mexico. While that does mean that UNP has some pretty substantial maintenance costs and capital needs to keep the wheels turning, it also gives the railroad a pretty substantial economic moat. Prolonged high oil prices have been a big boon to UNP. In general, rail shipping costs around one-fourth as much as trucking does per ton shipped, a cost advantage that typically sends customers setting aside the convenience factor of truck freight once fuel prices get past a certain point. >>5 Volatile Stocks to Buy More Of At the same time, UNP's efficiency has been ramping higher. Today, the firm's efficiency is as good as it's ever been. 2011 was a record year for Union Pacific from a sales, income, and cash standpoint. That excellent financial performance gives the firm plenty of dry powder to hike its dividend in 2012. Right now, UNP pays out a 60-cent quarterly dividend, yielding 1.9% at current price levels.