Full torque maybe, but full power won't be achieved straight away (Remember that power is force*velocity or in rotation terms torque*angular velocity - to achieve full power at low speeds would require silly high amounts of torque. Indeed, graph I posted in

#840 shows power ramping up fairly linearly to around 50kph before then flattening off and gradually increasing again at higher speeds (which corresponds to a flat torque to start which then drops away)

The relation between peak and continuous power is pretty nebulous as it's mostly down to thermal management of the entire system (motors and controllers) as far as I can tell, and indeed the way in which the continuous rating for these motors has been defined is not entirely clear either - is it a 1 hour rating, or a theoretical infinite power output in a room at 20°, etc? The complexity of modern VVF motors and inverters also makes calculating things a lot more complicated than DC motors!

Determining the necessary peak power is also a bit of a dark art, as it's dependant on the train parameters, loading, weather, and just how quickly you actually want to go! Doing an estimated worst case to get these to a balancing speed of 137.5mph up a 1:100 gradient with an extra 30t in passengers (~400 passengers) in a 30mph headwind with the rolling resistance parameters the same as I've used throughout, I get to a required power output of 5.4MW, which seems excessive, and a highly improbable situation. Taking Sharnbrook as a more reasonable worst case (1:120 at 110mph) you only need 3.4MW for the same 30t load and strong headwind, but with aerodynamic drag being the predominant factor at high speeds (dropping the headwind to zero in the Sharnbrook scenario drops power to 2.5MW) without knowing the actual drag coefficient and area it's all just guesswork and fancy graphs!

I will say it again though, the odds of Hitachi dropping the ball and making a 125mph unit that's incapable of reaching 125mph seems slim, so they've clearly got confidence in the ability of the motors to get these up to 125mph and beyond - the big worry ia that with only 8 motors and 2 traction converters, at anything less than 100% reliability they're gonna be pretty poor, particularly in leaf-fall!