It's not the electric motor torque that makes the difference. Caltrain used to use traditional locomotives, you'd have a single F40PH or MP36PH at one end pulling a bunch of unpowered carriages. Those locomotives were diesel-electric though, that is the diesel is only there to act as a generator while the traction motors are electric.
The Stadler KISS units are so much faster because they're EMU's (Electric Multiple Units), that is most of the wheels in a 7-car consist are powered with their own traction motors. An F40PH makes 3000 hp (2200 kW) while a Caltrain 7-car KISS consist can put out 9400 hp (7000 kW) continuous and about 50% more than that in short duration overload mode for starting. That's the reason it accelerates so much faster.
Traditional locomotive trains are completely obsolete in any sort of commuter service with frequent stops, there's just no way for them to keep up with EMU's or even DMU's. You can't solve it by just putting bigger engines on the locomotives, you wouldn't have enough weight on the wheels to make sufficient tractive effort.
The Stadler KISS units are so much faster because they're EMU's (Electric Multiple Units), that is most of the wheels in a 7-car consist are powered with their own traction motors. An F40PH makes 3000 hp (2200 kW) while a Caltrain 7-car KISS consist can put out 9400 hp (7000 kW) continuous and about 50% more than that in short duration overload mode for starting. That's the reason it accelerates so much faster.
Traditional locomotive trains are completely obsolete in any sort of commuter service with frequent stops, there's just no way for them to keep up with EMU's or even DMU's. You can't solve it by just putting bigger engines on the locomotives, you wouldn't have enough weight on the wheels to make sufficient tractive effort.