1900 led to plans to build two new transcontinental railways. The Canadian Northern, a successful system covering the northern part of the prairies, and the Grand Trunk (through its Grand Trunk Pacific subsidiary) both launched ambitious plans to expand. The government at first encouraged the two to come to some arrangement and only have one new line, but in the end no agreement was made and the government supported the expansion of both lines. The federal government itself built the National Transcontinental Railway, a line from Moncton to Winnipeg, passing through the vast and uninhabited hinterland of the Canadian Shield. Nationalization effort This aggressive expansion proved disastrous when immigration and supplies of capital all but disappeared with the outbreak of the First World War. The Canadian Northern, Grand Trunk Pacific, and Grand Trunk were nationalized by the federal government, which absorbed the debt of over two billion dollars. All three railways, along with the Canadian Government Railways (formed by the Intercolonial, National Transcontinental, and several smaller lines) were then merged into the Canadian National Railways in 1923. The years after the First World War saw only moderate expansion of the rail network and the age of the great railways were over in Canada. The automobile provided strong competition by the 1920s, and after the Second World War most passenger service was lost to airlines. The Canadian National Railways was one of the earliest diesel train operators in North America. The CNR experimented with self-propelled "oil-electric" cars starting in 1924. Diesels slowly became more prominent as yard switchers in the following decades. A prominent debut of diesel railway locomotion in Canada was in 1929, when CN No. 9000, built by the Canadian Locomotive Company using diesel engines imported from Britain, was used on the International Limited, the flagship train of the former Grand Trunk Railway. Postwar period The National Transportation Act of 1967 was an attempt at comprehensive transportation reform. It provided government subsidies for branch lines and passenger services, which at the time were still operated primarily by Canadian National and Canadian Pacific. In 1978, Canadian National passenger services were transferred to a new federal agency, Via Rail. CN was privatized in November 1995. See also History of rail transport by country Rail transport in Canada History of Canada Historical sizes of railroads List of street railways in Canada List of railway stations in Canada List of designated heritage railway