By Keith Laing
The route is intended to relieve traffic on Interstate 15, which connects the two sprawling cities.
As planned, the railway would come within 40 miles of a proposed California high-speed rail connecting L.A. and the San Francisco bay area. A future extension is planned to connect the two lines.
Reid's office did not say what Friday's announcement was. The senator has said in the past that the train would create 34,000 jobs in Nevada.
LaHood and Reid will appear at the University of Nevada, Las Vegas (UNLV) at 11 a.m. PST.