Complex sentence: The two special units had cables put on the front so they could be used to make a 3-unit set for longer trains-one of the units had the nose rebuilt with an access door, raising the headlight and changing the contour of the nose.
Split into simpler sentences: The two special units had cables put on the front so they could be used to make a 3-unit set for longer trains. One of the units had the nose rebuilt with an access door, raising the headlight and changing the contour of the nose.