You can... I took the entirety of my Godmother's cremains from Orlando Intl. Airport [MCO] to Ponce, Puerto Rico two years ago, for dispersal in the Caribbean sea. And I did it as a carry on (not checked). It just has to go through the scanner as its own package with nothing else in it. And it will show up on the scanner as one big blob. Just have the paperwork (death cert, etc.) with you.I can't see any reason why not, here's the list of prohibited items https://www.amtrak.com/onboard/baggage-policy/baggage-prohibited-items.html . Obviously the container should be well sealed, but if I could take some of my dad's ashes thru TSA on a plane to Hawaii, no problem.
All the more reason to bring the cremains as "carry on" and not in checked baggage. The TSA agents at MCO that handled my Godmother were very professional. I had a T-shirt in the box with the plastic container of cremains, only to keep it from flopping around in the Postal box. They made me take the shirt out and send the box through with only the plastic container of cremains. That passed without incident, and I was able to reassemble the box with t-shirt therein.I'm not sure why the TSA would be seen as any sort of authority figure on the transportation of cremains, but if you happen to bring any with you I'd recommend keeping an eye on anyone inspecting your luggage.
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