Is Tesla a frequent rail shipper? I got the impression that it wasn't (notwithstanding the rail facilities in Fremont), but with a factory of this size a rail connection is a obviously a must.
How did you figure the six miles? I can see the rail line on Google Earth, but I'm not really sure the exact spot of the factory. I would add that six miles is actually pretty long for a rail spur, and with the hills, etc., the routing might need to be more circuitous. Of course, I'm saying that without actually knowing the exact location.