1. A method for preventing a surge event occurring in an engine system including a turbocharger and a diesel engine operable at a plurality of discrete speeds, the method comprising: determining a current mass flow rate of the engine system; correcting the current determined mass flow rate based on a mach number corresponding to the current mass flow rate; determining a corrected turbocharger speed based on a mach number corresponding to the turbocharger speed; determining whether a surge margin is exceeded based on the corrected current determined mass flow rate and the corrected turbocharger speed; and controlling an operating load input to the engine system to prevent the surge event from occurring.