Complex sentence: The School lent its name to the tenth steam locomotive (Engine 909) in the Southern Railway's Class V of which there were 40.This Class was also known as the Schools Class because all 40 of the class were named after prominent English public schools.
Split into simpler sentences: The School lent its name to the tenth steam locomotive (Engine 909) in the Southern Railway's Class V of which there were in total 40. This group of locomotives was also known as the School's Class because all 40 were named after prominent English public schools.