Yet, it seems that Alderman must simply have counted the number of times 'M.P.' was observed in the Bradshaw's guide he used to acquire this figure, rather than considering that some directors sat on the board of more than one company. For example, the notorious George Hudson was Chairman of the Eastern Counties, Midland, York and North Midland and York, Newcastle and Berwick Railways, as well as being a director of the Manchester, Buxton, Matlock and Midland Railway. Nevertheless, he can only be counted once as the M.P. for Sunderland.
Consequently, my figure for the number of railway directors in Parliament is clearly more accurate. In 1847 the actual number of M.P.s who were directors was sixty, or 9.15 per cent of the 656 M.P.s that had been elected in 1845. Fourteen of these were also sitting in the House of Lords and overall the railways were represented in that chamber by forty-two individuals. Therefore, in 1847 102 individuals constituted the 'Railway Interest.'
 Alderman, Geoffrey, The Railway Interest, (Leicester, 1976), p.25
All other information: Glynn, Henry, Reference Book to the incorporated railway companies of England and Wales, (London, 1847)