Westinghouse automatic signalling system operated through electrified track circuits. This controlled signals based on the presence or absence of a train on the track ahead. Signals incorporated an arm that was raised when the signal was red. If a train failed to stop at a red signal, the arm would activate a "tripcock" on the train; applying the brakes automatically. Operation Early struggle for survival Apart from the electrification of the DR, Yerkes did not live to see the completion of the fast-paced construction works that he set in motion; he died in New York on 29 December 1905 and was replaced as UERL chairman by Edgar Speyer. Speyer was chairman of the UERL's backer Speyer Brothers and a partner in Speyer & Co. Sir George Gibb, general manager of the North Eastern Railway, was appointed managing director. The BS&WR opened to passengers on 10 March 1906. The GNP&BR followed on 15 December 1906, with the CCE&HR on 22 June 1907. The three tube lines quickly came to be known as the Bakerloo Tube, Piccadilly Tube and Hampstead Tube. Yerkes also did not live to see the UERL's financial struggle during the first years after the opening of the new lines. Because of greatly over-optimistic pre-opening predictions of passenger numbers, the lines failed to generate the income expected and needed to fund the interest payments on the UERL's substantial borrowings. In the Bakerloo Tube's first twelve months of operation, it carried 20.5 million passengers, less than sixty per cent of the 35 million that had been predicted during the planning of the line. The Piccadilly Tube achieved 26 million of a predicted 60 million and the Hampstead Tube managed 25 million of a predicted 50 million. For the DR, the UERL had predicted an increase to 100 million passengers after electrification, but achieved 55 million. The lower than expected passenger numbers were partly due to competition between the UERL's lines and those of the other tube and sub-surface railway companies, and the further spread of electric trams and motor buses, replacing slower, horse-drawn road transport, that took a large number of passengers away from the trains. The low price of tickets also depressed income. The crisis point for the UERL was the need to redeem the five-year profit-sharing secured notes on 30 June 1908. The UERL did not have the money. Speyer unsuccessfully tried to persuade the London County Council