British Railways Driver's Manual - High Speed Diesel Train (HST) - Drivers Static Duties
Incl, Preparation, Disposal, Immobilisation, Taking Over & Changing Ends.
Issue Date: Unknown - BR 33056/35 - Provisional Edition.
More information can be found here
Wikipedia -
British Rail -
Wikipedia - HST -
Testing
the HST Prototype -
Wikipedia - IC 125 -
125 Group