Especially popular in Europe, intercity passenger rail is an excellent alternative to driving. Like mass transit rail within urban areas, it can carry more passengers per vehicle than buses and is a very efficient mode of transportation for that reason. Compared to cars, taking the train can be significantly more energy-efficient on a per-passenger mile basis.
However, in the United States, rail freight companies own the railways themselves. This can mean that passenger trains have to take a backseat to freight trains, even making stops to let them pass. This situation makes it difficult for passenger trains to stay on schedule, and as a result they tend to be a less popular choice in the U.S.