http://www2.warwick.ac.uk/services/library/mrc/subject_guides/family_history/rail/asrs/
The Amalgamated Society of Railway Servants of England, Ireland, Scotland and Wales was founded in 1872. In 1892 it absorbed the Amalgamated Society of Railway Servants of Scotland. It was the dominant partner in the 1913 amalgamation with the General Railway Workers’ Union and the United Pointsmen’s and Signalmen’s Society which established the National Union of Railwaymen.
Volunteers are currently indexing the first of the ASRS membership registers. The ASRS membership registers. The index to entries for members who joined between 1872-1888 (with a few out-of-sequence entries up to 1899) is available as a Microsoft Excel spreadsheet (it may take a while to open initially). It only includes those individuals who were still members of the union in 1897, the year that the register was compiled.