The original Metropolitan District Railway (as it was then called) opened in December 1868 from South Kensington to as part of a plan for a below-ground "inner circle" connecting London's main line termini. At first, services were operated using wooden carriages hauled by steam locomotives. Electrification was financed by the American Charles Yerkes, and electric services began in 1905. The railway was absorbed by the London Passenger Transport Board in 1933. In the first half of the 1930s the Piccadilly line took over the Uxbridge and Hounslow branches, although a peak-hour District line service ran on the Hounslow branch until 1964. Kensington (Olympia) has been served by the District line since 1946, and a short branch to closed in 1959. The trains carried guards until one-person operation was introduced in 1985.