*Note: As Action Comics is an ongoing title that will progress and Superman's ability/power will obviously increase given time, feel free to point out exactly when Morrison's Superman will be powerful enough to beat Thing for the majority. As of now, we'll go with AC#1 as a judge and weigh in more as the issues and stories develop.
I think you could make a solid case for AC#1 Superman beating Ben right now. In terms of durability he's not as tough yet, but they're probably close in strength and Supes has the edge in speed.
I don't know how quickly he'll develop in AC, but I'm guessing it won't take very long to decisively win.
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"And then there was nothing. A once broken something now void.
And on the first day, Doom spoke... 'Be.'
And then there was life."
I dunno. Those kinds of trains can weigh several hundred tons, and going 200mph hits pretty hard. Especially seeing as Superman was trying to slow it down, not stop it dead.
Not saying it puts him above Thing, but I'd say it's close if it's the standard for him at that age.
Oh most definitely I'm just saying at the time of the incident I think Thing would fair better. He's taken far harder shots in his time and Superman is just starting out so I'd have to see more to see where this scales on his (Superman's) average.