British Rail Train-Crew Manual - 2500H.P. Type 4 British Railways Diesel Electric Locomotives Nos D138 - D193 (Later Class 46) - 
Drivers Guide and General Information - July 1962    -   BR 33003/98.


More information can be found here Wikipedia - British Rail Class 46  -  Derby Sulzers Website 
More Information Regarding Preserved Class 46 Locomotives can be found on the following websites:  Preserved-Diesels  -  Llangollen-Diesels