Question

unlike the steam locomotive, which required an hour or two of firing up before it was possible to move under its own power, nearly full power could be summoned almost instantly from the cold engine of a diesel locomotive

Answer 1

Heya
Your answer

(A) it was possible to move under its own power, nearly full power could be summoned almost instantly from the cold engine of a diesel locomotive 
(B) it was possible to move under its own power, the diesel locomotive's engine, when cold, could produce nearly full power almost instantly 
(C) it could move under its own power, the diesel locomotive could summon nearly full power from a cold engine almost instantly 
(D) moving under its own power, the cold engine of the diesel locomotive could produce nearly full power almost instantly 
(E) moving under its own power, almost instantly a diesel locomotive could summon nearly full power from a cold engine