I'm pretty amazed someone would claim that Trax is only limited to a small area of downtown Salt Lake.
SLC mayor Ralph Becker says, "by the end of 2013, we will have witnessed the largest expansion of an urban rail system in the nation." [1]
"70 miles in 7 years" seems pretty ambitious to me. [2]
[1] - http://www.sltrib.com/sltrib/news/55680450-78/salt-lake-beck...
[2] - http://www.rideuta.com/mc/?page=Projects-Frontlines2015
Aerial Map: https://www.google.com/maps/ms?ie=UTF8&oe=UTF8&msa=0...
The valley really needs to build up some density to make transit really work, but its difficult with all that land available + a conservative Republican state government (along with the people who vote for that government).