Lloyd's building consists of three main towers and three service towers around a central, rectangular space. Its core is the large Underwriting Room on the ground floor, which houses the Lutine Bell within the Rostrum. Also on the first floor is loss book which for 300 years has had entries of significant losses entered by quill. The Underwriting Room (often simply called "the Room") is overlooked by galleries, forming a high atrium lit naturally through a huge barrel-vaulted glass roof. The first four galleries open onto the atrium space, and are connected by escalators through the middle of the structure. The higher
London Underground S Stock (ex-Metropolitan Railway) used with two 1925-built prototype driving motors. In 1925, two driving motor cars were built as prototypes for what would later become the T stock. In the London Passenger Transport Board numbering scheme, they became 2598 and 2599. After the trailer cars were withdrawn from service in the 1940s, the two driving motor cars remained in service on the East London Line, being used with a 1923-built control trailer. These three cars were withdrawn in 1950. London Underground S Stock (ex-Metropolitan Railway) S stock is the designation given to one train of eight cars by London Underground in the 1930s.