Warren Buffett just turned 79, but to quote a great line from the Washington Post, he invests "like an 8-year-old boy in the 1950's." Coca-Cola, Dairy Queen, candy, chewing gum and now a choo-choo set. But seriously, what does his purchase of Burlington Northern Santa Fe tell us about the economy?

Buffett already owns 23% of BNSF, but in Berkshire Hathaway's biggest deal ever, he's buying the rest. Here's what Buffett said on CNBC this morning:

Rails last year moved 40 percent, more than 40 percent, over the country. They moved more than all those trucks, just the four big railroads. It's a very effective way of moving goods. I basically believe this country will prosper and you'll have more people moving more goods 10 and 20 and 30 years from now, and the rails should benefit. It's a bet on the country, basically."

It might also be a bet that energy prices are going higher. From Bloomberg:

"As oil prices go up, higher diesel fuel raises costs for rails, but it raises costs for its competitors, truckers, roughly by a factor of four," Buffett told shareholders in 2007 at his company's annual meeting. "There could be a lot more business there than there was in the past."

Finally, the BNSF deal might be a bet on China. From the Washington Post's Economy Watch:

China craves the coal and other raw materials that the U.S. produces. Those commodities fuel the great economic engine that is China, which is the factory to the world. U.S. coal and goods are sent via rail to Pacific ports and then shipped to China. With his round-out purchase of Burlington Northern, Buffett thinks China will continue to be strong.

By the way, Buffett also announced a stock splitting plan. Berkshire's class B shares would go from $3,000 a piece to only $65 a share!

Of course, class A shares are still priced at just under $100,000. Each.