Railroads changed the nature of logging, as the business of lumbering was once called. They made it easy to transport lumber to far away markets and mills and railroads made it possible to log in places far from rivers and streams. Yet railroads didn't replace logrolling, at least not right away. Logrolling, floating lumber down rivers and streams, was the cheapest way to move logs great distances. But logrolling was also a dangerous activity. Obstacles, such as boulders and rocks, often caused logs to pile up. When they did, the logs had to be unjammed. Loggers waded in freezing water chest-deep to clear log jams and rode logs, armed with long wooden poles, to free lodged logs. The icy water made loggers sick and the force the unlocked lumber released caused many to drown.