[5] Its main task was to follow the progress of legislation which might affect railways, attempting to persuade MPs and Lords to vote in the 'railway interest', and giving evidence to parliamentary committees.
The perceived threats to profitability, through regulation of the rates which the 'monopolist' railways could charge, led to several moderately-large companies joining the major ones in the association, finally giving it national coverage.
Much of the actual lobbying work of the Association devolved onto its parliamentary subcommittee, which consisted of Lords and MPs from the member companies' boards.
[7] The association had a small permanent secretariat, paid for by a precept of one or two shillings per £1,000 of the gross revenue of each participating company.
[12] The association's role was necessarily reduced during World War I when parliamentary interest in domestic transport matters was low, railways being managed for the war effort under the provisions of the Regulation of the Forces Act 1871, but it gained in importance when the newly established post-war Ministry of Transport decided to deal with the railway companies jointly through the Association.
The parliamentary members' council was abolished, severing the direct link with Parliament, and the four new general managers constituted a standing committee of the association.
Briefings of independent railway-linked Lords and MPs continued however, for example in the companies' 1938 'Square Deal' campaign for reform of freight rates' legislation in the face of road competition (which was overtaken by the onset of war in 1939)[15] and in the run up to the Transport Act 1947 which nationalised the railways.