When I spoke with the rep from CORP a week or so ago, I asked her if there was any chance of running stack-trains over the Siskiyous. She said the rails in the tunnels would either have to be lowered, or the ceilings would have to be raised higher, which would be more cost than the company is willing to expend. The curve in tunnel 14 would also have to be delt with.

Clearly, modern double level AMTRAK passenger cars in addition to their length would not be compatible with the Siskiyou summit line.

When tunnel 13 reopened after the fire, they took a few old private passenger cars up for the grand opening, but stopped short of entering the tunnel because of height issues. It was a nice ride though. :)