This little 0-6-0 is all metal no plastic. mostly a white metal, but a couple spots also show brass. 
The one screw is missing that holds the pilot on. note the jewels in the. markers.
The bell has the gong in it and it moves seperape from th bell
No markings on the underside at all. the gear is brass as well
But those couplers. prototype look. that coupler bar does lift the coupler pin, opening the coupler itself. this is not a mantua or bowser from what I can see. but who built it?
SHane
The headlight is screwed on. it is a little loose
That coupler was from Model Die Casting, and I still have a couple of them around here, somewhere in my workshop.
…and this is the early version of Kadee couplers
Wayne
It would appear to be a Model Die Cast locomotive. They were kits at one time then built but very little details. There is added details on yours. Probably some of English model supply or Carry. The semi blind center driver looks like it was shaved down but I have seen them like that.
Pete.
Looks like an Aristacraft with a Devoe coupler (MDC had the rights to that coupler later in its life).
It does run. But takes a lot of power to get it running. It does need a serious cleaning and maybe a new motor. Or new magnets for it.
I was thinking of adding a detail kit. Since what is there is mostly mold on details.