From the 2007 BRK Annual Report...
For fun, lets do a fair "replacement cost" estimate on the 94,000 railcars alone.
94,000 x what.?
Made out of steel, the boxcar cost about $45000 a copy in 1980. A buddy of mine, says that $90,000 would be a fair price to pay for a mid-use rail car which can be depreciated over about 50 years.
94,000 x $90,000 = 8.46 Billion.... just in railcars alone. Furthermore, consider that the Marmon Group is composed of 125 different companies.