How do とは and に/された work in 「N700系とはどこが違う？N700Aに搭載された性能」


I saw this on the cover of a book about trains that was at least similar to a
magazine:

>
> [N700系](http://ja.wikipedia.org/wiki/%E6%96%B0%E5%B9%B9%E7%B7%9AN700%E7%B3%BB%E9%9B%BB%E8%BB%8A)とはどこが違う？
>
> N700Aに搭載された性能

This is a little confusing:

  1. とは is used to define things. It is often used either in a question asking for a definition or a dictionary entry that actually gives a definition. どこが違う？ does not sound like a question asking for a definition.

  2. As for the second sentence, it almost looks like "The ability by which it was loaded by N700A." That is obviously not the meaning of the sentence.

Maybe this is something vaguely in the ballpark of the meaning of that phrase?

> What's new and different in the N700 series [of train models]?
>
> The N700A, which is superior in terms of capacity

What is the translation, and in particular, what am I missing here?




Here, とは is just pointing out that we're defining a characteristic of the N700
group. (The と is the quotative particle, but I don't think that really helps
in parsing this.) どこが違う？ is not asking for a definition _per se_ , but for
defining a characteristic.

Your translation is pretty close. Literally, I'd translate it as something
like:

> Where is the difference from the N700 line [of trains]?  
>  The performance (or efficiency) that was equipped by the N700A.

Or, more naturally:

> What's different from the N700 train models?  
>  The N700A's performance levels.

