K.B.
Depends on the size of the electric train, there are some that are larger and I would say is fine for a kid (they usually are plastic and track is a littler smaller then a piece of bread). I would not get the smaller size ones because they are easier to break since they will have real metal, small parts and easier mess up if holding/playing with.
The wooden ones are nice but at age 5 1/2 my daughter has out grown it and we are already thinking of getting an electric one for around the Christmas tree this year or next year. She first got the wooden train, tracks & table when she was 2 years old so she has had it for 3 1/2 years now, soon it will be passed on to her new cousin this summer.