Unlike the steam locomotive, which required an hour or two

[lijingli401]

why is not E

the original comparison starts with "Unlike the steam locomotive, ...", followed by a modifier. you can kill this modifier in your consideration of the basic structure of the sentence, as modifiers don't count as part of basic structure.
the next part is the main clause. because the comparison is to the steam locomotive, you MUST start the main clause with "the diesel locomotive". you shouldn't precede that with anything - such as the adverb (almost instantly) in choice (e). in order for the comparison to be clear, you MUST begin the main clause with the item that provides the other half of the comparison.

understand. but I have another problem, -->focus on meaning CE ,
like "almost instantly a diesel locomotive could summon nearly full power from a cold engine" is different from the "the diesel locomotive could summon nearly full power from a cold engine almost instantly"
does some differences exists in meaning about C and E here?

[RonPurewal]

understand. but I have another problem, -->focus on meaning CE ,
like "almost instantly a diesel locomotive could summon nearly full power from a cold engine" is different from the "the diesel locomotive could summon nearly full power from a cold engine almost instantly"
does some differences exists in meaning about C and E here?

there's no difference.
"(almost) instantly" is an adverb.
there's only one action that could be modified by this adverb -- i.e., "could summon..." -- so the adverb has the same significance in either position.

[namnam123]

yes, oa should be C.

The point I want to discuss here is the use of "moving" in E. Is "moving" in E right?.

Many times I posted here but I do not see the reply.

[RonPurewal]

yes, oa should be C.

The point I want to discuss here is the use of "moving" in E. Is "moving" in E right?.

it makes grammatical sense, but its meaning isn't really accurate.
the sentence is intended to show that a lengthy process of preparation was required just to create the potential for motion (= COULD move), not necessarily motion itself.