These lines are important because they handle local traffic that, if not moved by the railroads, would either move by truck over state and local roads or would cease to move which could cause businesses to close or relocate. Trains typically carry heavier weights using much less fuel than trucks do. This is because the friction involved in moving steel wheel vehicles on steel rails is about a tenth of that involved in moving rubber-tired vehicles on pavement. Consequently, the energy required to move the same weight is much less on rails than on pavement. The end result is that far less energy is consumed in shipping by rail than by truck, which means that shipping by rail generates less pollution, thus preserving air quality.
Rail serves as an alternative shipping mode.
This option could become increasingly important in the future if barge traffic on the Columbia River is affected by draw downs to save endangered salmon runs. It already is important to growers in areas served only by county roads that are closed when there is frost or ice. They also help to keep the transportation system healthy by providing shippers competitive alternatives.