Yes - trains are extremely crash resistant, which is one of the many nice features. Short of an ICE train managing to hit a bridge support head on as happened a few years back in Germany, they're so safe that they and ships are about the only transport that don't worry about seat belts.
(Which leads to another nice thing - being able to get up and walk about.)
The 250 pax may well be wrong - I'm definitely guessing there. However, having walked a fair way down that train, I can affirm that the passenger density is extraordinarily low. This isn't so much a train for getting people from one place to another, it's a mobile hotel, a cruise ship on rails. A Japanese Hikari Shinkansen would be running 1000 pax in a shorter consist.
The Rocky Mountaineer that aardvark179
transferred to stops at night, thereby saving all the cabin weight and bulk, and the requirement for evening meals too. I'd expect that to be at least twice as efficient.