noun
railmotor; railcar with internal combustion engine
Technical term for a self-propelled railway vehicle powered by an internal combustion engine, distinct from electric or steam railcars.
この路線ではディーゼル内燃動車が使われている。
Diesel railmotors are used on this line.
気動車 is a more common term for a diesel railcar, while 内燃動車 is a broader technical term that can include gasoline or other internal combustion engines.
Compound of 内燃 (internal combustion) + 動車 (powered vehicle). A technical term likely coined in the early 20th century with the development of internal combustion engine railcars.