rise in value once the UERL's tube railways were operational and producing a profit. Investors in the notes would gain the double benefit of the growth in share price and interest. Engineering works Electrification of the District Railway Before its takeover, the DR had carried out some joint electrification experiments with the Metropolitan Railway (MR), the other sub-surface line with which the DR shared the Inner Circle. A section of track between Earl's Court and High Street Kensington was electrified with a four-rail system and a jointly owned test train operated a shuttle service between February and November 1900. Having proven the practicality of electric traction, the two companies set up a joint committee to select a supplier of equipment for the electrification of their networks. The committee's preferred system was a 3,000 volt, three-phase alternating current system proposed by Hungarian electrical engineering company Ganz. The system delivered current by overhead conductor wires and was cheaper than alternatives using power rails and required fewer electrical sub-stations. An experimental line had been constructed by Ganz in Budapest, although the system had not yet been adopted for the full-scale operation of a railway. Before the appointment of Ganz could be finalised, Yerkes took control of the DR. He and his engineers preferred the low voltage direct current conductor rail system they had worked with in the United States and were intending to use on the tube lines when they were constructed; they rejected the Ganz system putting the DR and the MDETC into dispute with the MR which wanted to proceed with the Ganz system. After some acrimonious debate between the two companies, some of which was carried out in public through the letters pages of The Times newspaper, the dispute went to arbitration at the Board of Trade. The decision was made in December 1901 to use the four-rail system, although the arbitrator, Alfred Lyttelton, was critical of the DR's unilateral decision. Victorious, the MDETC quickly began the electrification of the DR's tracks, starting with an extension from Ealing Common to South Harrow that opened with its first electric service in June 1903. Conversion of the rest of the DR's tracks was completed in mid-1905, although failure to coordinate installations with the MR meant that the first electric services on the Inner Circle from 1 July 1905 were disrupted for several months due to equipment failures on the MR's trains. Power