Specifically a JR Class 205 electric MU, as sold to Indonesia after their retirement in Japan (The modeler is also in Indonesia). Now, I don't know if this is specifically O scale, but it's close, and his building methods look to be quite repeatable, even building his own wheelsets and power trucks (although I don't know where he sources the motor units).
Wait till you see them running (he built five cars) on his layout at the end. Plywood central? Meet Cardboard Central .
(yes, he has videos on how he built the track and switches)
---PCJ