In my writings I tend to classify electric vehicles and other vehicles that match the above title by their location in our transportation networks. That is:
- Road Vehicles
- Tracked Vehicles
- Aircraft
- Maritime Vehicles (a.k.a. ships and boats)
World-wide most tracked vehicles are already electrified. If a government agency is going to the trouble of laying a track system, it is not that much more expensive to put in an electric supply and equip the locomotives and/or train-cars to tap into that supply. Also, once this is done the operating cost is generally much lower than fossil-fueled trains.
The reason that diesel-electric (a generator driven by a diesel-engine driving electric traction motors) is dominant in the US (etc.) is that we have very long distances between metro-areas in many regions, and having just passive tracks in these stretches reduces the cost of installing and maintaining these tracks by a huge amount. Also, these sections are mostly used for freight, not passengers.