VIKENA,just as a rule of thumb remember that 'gradient' is climb.
To figure out a 2.4% simply mulitply the basic figure of 60" per nautical mile as 1%(6000'-mile)..ergo 2.4% is 144' per mile x the grounspeed equals rate of climb required.
144' x 145KNOTS =350'rate of climb(MINIMUM)on 'one engine'
In Canada the SID rate of climb is 200'/mile,as stipulated in the Canada Air Pilot for the edification of questionable departures.
Some carriers depict 'escape routes-engine out'depending on what terrain clearance guidance they utilize..ICAO,or FAA(reduced swath limits)
cheers
