[StACase]

Railroads have used Diesel-Electric locomotives for years. But then a locomotive needs to be heavy.

[thackney]

Railroads have used Diesel-Electric locomotives for years.

Mining has used diesel-electric hybrids for years as well.

Liebherr T282B: world's biggest diesel-electric truck

592 tons, 2.7 MWatts

[BurbankKarl]

The new locomotives all have hybrid technology too

[RS]

"Railroads have used Diesel-Electric locomotives for years."

Different concept and requirements.
The electric motor on the drive wheels are used to provide the massive low speed torque needed to start a freight train moving.
I can't imagine how many low gears you would need to do it with diesel alone.

[UpAllNight]

--Railroads have used Diesel-Electric locomotives for years. But then a locomotive needs to be heavy.--

I don't think the weight is due to batteries.