That narrows it considerably but there are no John Hammond deaths in Blackburn between 1960 - 2007
If he only took over in 1958 he may not even have worked for the railways in 1939.
He could have lived in any locality and returned there after 1960. Preston was not that far but there is only one death in Preston and he was William John F Hammond b 1891 meaning he would have been 67 in 1958. The 1939 entry for him does not support a railway connection
The John Leonard Hammond b Liverpool 1910 married and died there in 1995
An potential alternative - John Leslie Hammond, b.1910 Carbrook Sheffield
Births September qtr 1909
HAMMOND John Leslie Sheffield 9c 691
If you have looked at the 1939 register I suspect you have looked at the wrong entry
Births September qtr 1909
HAMMOND John Arthur Wakefield 9c 27
Death March qtr1981 Wakefield John Arthur Hammond aged 71 Born 30 May 1909