Ministers will join in the effort, using forecasts that show commuter trains serving the four biggest cities linked by the line - Birmingham, Leeds, London and Manchester - during peak will be carrying up to twice as many passengers as there are seats by 2033 when the full route is due to open, assuming annual passenger growth of 1.5 per cent. A study by accountants KPMG will also predict that the line will create hundreds of thousands of new jobs in the regions.