The Globe and Mail reports in its Saturday edition that stocks considered oligopolies -- in which a few players dominate one sector -- have generated returns that have easily beaten the S&P/TSX Composite Index over the past 30 years, and they have done it with lower volatility. The Globe's David Berman writes that one of the best oligopoly is the venerable Canadian Pacific Kansas City. Its 10-year return, annualized, is 13.5 per cent. You can understand why no one is building new freight railways in North America when you consider the cost of maintaining existing ones: an average of more than $23-billion (U.S.) a year over the past five years. Now imagine what it would cost to build a network from scratch. Despite immense capital expenditures, the North America-wide oligopoly has thrived through consolidation, and a key reason is its efficiency. "Since one rail car can carry the volume of approximately four trucks, and less fuel is consumed during the transportation of rail freight as opposed to other modes, the greater the distance, the more efficient rail is," Adam Anderson at RSI Logistics said in a statement. CPKC may also enjoy operational advantages after CP's merger with Kansas City Southern last year.