text: It might help if trains could be run as "container" trains, where tractor trailers could be lifted whole onto rail cars, locked down, and transported.
  
  However, there is still the problem analogous to private cars vs public transit. You still have to be travelling on a public transit route to be able to benefit, whereas private car (or tractor trailer) is more flexible in its origin an destination, and you don't have to deal with public transit schedules.