Supplementary Operating Instructions were issued irregularly and combined updates to multiple official documents into one; the source documents should be read in conjunction with the SOIs to appreciate the change in the rail network and operating methods over time. They often combined updates published elsewhere in Periodical Operating Notices with other amendments. See also the list of Periodical Operating Notices and Sectional Appendices in the library.
British Railways North Eastern Region
- 25th October 1958
- 7th March 1959
- 1st October 1960
- 4th March 1961
- 7th October 1961
- 7th April 1962
- 16th March 1963
- 21st March 1964
- 16th January 1965
- 4th December 1965
British Railways Eastern Region
Northern Area
- 3rd November 1972
- 9th May 1970
- 2nd June 1973
- 8th February 1975
- 6th March 1976
- 6th October 1979
- 1st August 1981