FUD Wrote:
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> Curious about the lead picture in today's
> Trainnews: I thought there had to be something Not
> A Tank Car between the locomotive and a string of
> tank cars. Nothing there in the photo - just tank
> cars. Unless the photo is of the end of the train
> (with a trailing distributed power unit) instead
> of the front...

In the scenario you're asking about, train placement restrictions are dictated by the commodity currently in (or last in) the car, not by the type of car.

Do you see a highly-visible diamond shaped placard with a number on the car? No placard = no placement restrictions = no buffer car required.

You can find lots of information about this by doing an internet search.