A Class 769 Flex will have a mass of around 156 tonnes and have an engine output (not at the rail) of 1050hp. This gives a hp/t of 6.7.
A 4 car Class 150 has a mass of 153 tonnes and has a engine output (not at the rail) of 1140hp.
This gives a hp/t of 7.67.
It's not just the amount of power available from the prime mover that ultimately matters. As has been discussed further up this thread in various posts, the main issues are:
a) the power at the wheel at key points in the intended service duty
b) the level of adhesion available with which to apply that power
c) the impact of the load (passenger) on the adhesion and acceleration
d) the durability of the traction in service
There are probably other issues but those are the main items for a passenger train, so:
a) in the case of DMUs, and this discussion, it is manily determined by the design of the transmission. In the case of a conventional DMU, the transmission is usually a hydraulic torque converter which acts as a transformer between high input speed low torque, and low (including zero) output speed with maximum torque. In a diesel-electric transmission, all of the shaft power on the generator is fed to the generator as the engine can be run continuously at the speed in which peak output is available.This is then applied to the wheels to provide maximum torque from standstill. The engine can be operated at its optimum speed almost throughout the full speed range of the train.
In practice, thetorque converter is extrememly inefficient when the input to output shaft speeds are furthest apart, i.e. on starting. For the diesel electric transmission, the full power available at the shaft can be used at the wheels
b) for the adhesion calculations for the classes 319 and 769, see my post #2700. Here the difference between a 319 empty/loaded/crush loaded and a 769 similarly loaded are quite small. The performance ofa 319 when fully loaded is adequate for the most demanding service so it's use on even quite busy secondary lines in the North (or elsewhere) are not likely to provide too many surprises.
c) unless a new maximum loading of crush load on a 769 (and then adding in say 15t for the gensets etc.) is required, there shouldn't be any issues when fully loaded.
d) diesel-electric transmission has been in use since the beginning of diesel trains. It's deployment and maintenance is a known quantity and provided none of the new components have durability issues, (mainly the genset), the 769s should provide reasonable service and running costs, especially compared to a torque converter transmission.
According to this article
https://www.railengineer.uk/2018/09/27/bi-mode-good-tri-mode-better/ the 769 will put 550 kw to the rail which is around 740hp. I don't know the horse power at the rail figure for a Class 150 so i can't compare.
This means that 70% of the 769's engine output is available at the rail with the rest being auxiliaries and efficiency losses.
A Class 769 Flex will have a mass of around 156 tonnes and have an engine output (not at the rail) of 1050hp. This gives a hp/t of 6.7.
A 4 car Class 150 has a mass of 153 tonnes and has a engine output (not at the rail) of 1140hp.
This gives a hp/t of 7.67.
According to this article
https://www.railengineer.uk/2018/09/27/bi-mode-good-tri-mode-better/ the 769 will put 550 kw to the rail which is around 740hp. I don't know the horse power at the rail figure for a Class 150 so i can't compare.
This means that 70% of the 769's engine output is available at the rail with the rest being auxiliaries and efficiency losses.
But as above, the key is to at what speeds the power is available and at what stress levels to the engine and transmission.