Carrying Pony Bottles on AmTrak Same Rules as Flying?

[Scubalot]

Update as of 25 May 2011:
Amtrak - Baggage Policy and Information prohibits from both Carry On and Checked Bags:

Canisters, tanks, or other devices containing propellants
*Oxygen equipment for medical reasons is allowed onboard with restrictions.​

That prohibition seems to cover pressurized scuba tanks.