Wow, that's big! Reno always made sense - structurally cheaper than CA, but closer to the Fremont factory than even Los Angeles.
Also, I hate business tax incentives, but $500M for a $5B factory + 6500 jobs is not terrible.
I'm not sure about the rail lines, but I can imagine a lot of delays in infrastructure in winter either way. At least for a Fremont-LA line, you won't hit those snags in winter.
I doubt these will be being shipped by truck given the quantities we're dealing with. I also would not doubt an improvement in the infrastructure for a corporation bringing 6500 jobs and $5bn into the economy.
There's an example of that kind of rail-clearing engine in Skagway, Alaska. I saw it there just over a month ago. That snow machine isn't used anymore--an historic museum piece on exhibit--but close up it is impressive.