Missing stopper, like many of these. The stopper is neccessary to build steam pressure to drive the wheels.
In lieu of the stopper some have suggested using a cork, although the stopper has a flange that locks it in place which the cork wouldn't have. I took this train teapot apart to clean it. The instrument gauge plastic panel in the cab has two plastic snap ins, one broke off inside. With a little patience and some super glue this may be fixed.
The black handle was nearly paralell with the roof top so I bent it back to it's near original position. There are some blemishes and paint loss such as the corner of the cow catcher and the whistle. There is a bolt inside the smokestack that is loose, so the smokestack can be pulled straight up and out. The top of the smokestack looks like it is a cap and it may be possible to open the top of the smokestack with a knife blade or similar to then be able to screw in the bolt which helps to hold down the front of the kettle top. Please see the pictures for condition.