With likely increase in desalination plants in the West, are there opportunities for rail?
First, there is no way that water - even if limited only to agricultural irrigation - can be handled in existing petroleum pipelines.
Now so far as rail transport, the good news is that if such a train spills, so what!!! A Megantic with a water train
But then we revert to the usual arguments; high initial capital costs against the lesser operating costs of a pipeline over rail. An existing rail route from, let's say, the Pacific Ocean (SP Coast Line) to the San Joaquin V alley (ATSF or SP) is already there. The only constraint coming to mind is the publicly funded improvements made to those routes for passenger trains. No doubt, limitations (hours, length, weight) have been placed (as they should be) on freight train operations.