Question: What is the name of the international company set up in 1977 by English composer and impresario of musical theatre whose well-known works include "The Phantom of the Opera" and "Jesus Christ Superstar"? 
Sentence (from "Really Useful Group"): The name is inspired by a phrase from the children's book series "The Railway Series" in which Thomas the Tank Engine and other locomotives are referred to as "Really Useful Engines".
Relevant evidence: No