Oh, God, I made that calculation so many years ago,... back when the Viewliners were ordered... that I would need to redo it with current numbers. Both costs and ticket prices have changed. Sorry, haven't the time right now.
It's buried deep in the Amtrak Unlimited Archives somewhere.
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The big political issue is those damn "fully allocated" costs. If you use true avoidable costs, most of the long-distance trains are profitable already. But when you "allocate" a portion of the costs from the central backshops, reservation system, etc. to them, then they look "unprofitable". This is bogus because if you cancelled these trains those costs would just get reallocated to Acela & Northeast Regional, making *them* look unprofitable.
What Amtrak needs is more train service to spread those fixed costs out over. And politically, Amtrak needs to report the "allocated" fixed costs and the real avoidable costs *separately*. Which they were tasked by law to do in 2008 but they have somehow not bothered to do.