You're all misunderstanding the purpose of a railroad company. As with all businesses, their #1 goal is to make money for the owners. It's not to run trains, employ people, or sell other goods or services. Those are, of course, what they do to make money, but there's a balance between spending money to make money. Ideally, if they could make money without actually spending any, that would be the way to go (see: theft, fraud, etc). So, when traffic is down or interest rates up, big spending is postponed or eliminated.

Big bridges (Spokane River? Mississippi?) cost a lot of money. Sometimes it's cheaper to keep fixing things rather than replacing them in the short term. The short term can be pretty long if downturns continue. Downturns can be created with rates and operating practices, which offers another way to postpone big spending items. All the while, dividends continue and stock prices stay high. Elementary, my dear Watson.