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
S1 (Rhine-Main S-Bahn) opened in stages between 26 September 1839 and 19 May 1840 and has been used by S-Bahn services since 1978. Between Farbwerke and Frankfurt-Griesheim this service shares the Main-Lahn line with freight and shunting operations. National and regional services use the parallel running Taunus railway in this section. The Main-Lahn railway was completed on 15 October 1877 and has been used by S-Bahn services since 1978. The city tunnel is an underground, pure S-Bahn route used by almost all services (except for the S7 service which terminates at the central station). The tunnel was opened in four stages in 1978,