I came across this tidbit about Amtrak in an in-flight magazine over the Christmas break.
Amtrak isn’t known for watchlike precision because it owns only 30 percent of the tracks it traverses. In 2007 alone, it had to pay other railroads $92 million in track-use fees. Its trains often wait for freight trains to pass, which in the U.S. outnumber passenger trains 30 to one.
This illustrates how services are bounded by the limits of their system design.