This is how most modern diesel (actually diesel-electric) trains work.
The issue with a big diesel engine like this actually turning the prop or wheels is the size of the transmission required. The engines are massive and the transmission would also be massive to cope with the power and torque. You also eliminate a moving part so much more reliable.
It seems so backwards to me to convert diesel into power and use that to drive an electric motor. It seems so inefficient, but I supposed it wouldn't be a thing if it was inefficient.
The issue with a big diesel engine like this actually turning the prop or wheels is the size of the transmission required. The engines are massive and the transmission would also be massive to cope with the power and torque. You also eliminate a moving part so much more reliable.