Complex sentence: This plant remained in service until 1920, when the two turbo-generators were relocated at Ultimo PS as No3 +4 and the four boilers were demolished to make room for the high-pressure plant.
Split into simpler sentences: This plant remained in service until 1920, when the two turbo-generators were relocated at Ultimo PS as No3 +4. The boilers were demolished to make room for the high-pressure plant.