It continued to expand after the LER became part of the London Passenger Transport Board in the 1930s and as the organisation passed through various successor bodies up to TfL, London's transport authority since 2000.[79] The Covent Garden building has on display many examples of buses, trams, trolleybuses and rail vehicles from the 19th and 20th centuries as well as artefacts and exhibits related to the operation and marketing of passenger services and the impact that the developing transport network has had on the city and its population.[80]