S.V.R. S&T Department
http://www.svrsig.org/ diags/S190.htm
The dog chart and associated locking table, derived from the dog chart, show the position as at 13 June 1963. In September 1942 the frame was converted to V.T. 5 bar locking. In June 1963 the signal backing up the down main (no. 18) was taken out of use and lever 18 made spare and the locking has been updated to show this change. A contemporary box diagram may be consulted in the publication 'Signal Box Diagrams of the GW and SR by G.A.Pryer, volume 20, GWR Berks and Hants lines'.
In February 1965 a single disc 33 replaced signals 33 and 36 and disc 37 replaced signals 35 and 37, moved into the loop lines becming shunt moves rather than running moves. Amendment A of the dog chart and associated locking table, derived from the dog chart, are updated to show this change.