There has been talk of a highspeed train from LA to LV, but its hard to maintain the tracks for bullet trains in the extreme temperatures you find in the deserts around Vegas.
Plus the CA environmental wackos would demand 20 years of studies on all the plants and animals that could potentially be effected by a trainline like that. By the time the environmental wackos and politicians get through with it, there would be no financial way to pull this off.
yea I don't believe there is any rail line bewteen Barstow and Vegas...the AT & SF and the SP entered California via Needles (~highway Route 66) as far as I know