The population at the south end of the Imperial Valley would not appear at first glance to be enough to support a passenger service. But, there's Mexicali just over the border with a population of 750,000 IIRC. Am sure also Uncle Pete would be unenthusiastic about a project like this, unless they could figure out a way to get public sector money to pay for the necessary upgrades to the line between Niland and Calexico. I think most of the line is 40 MPH tops, maybe even 25 MPH.