caption: The decoder can be positioned as shown or laid flat on the same section. I found the clearance between the leads and the rear of the smoke box door of the loco was minimal when laid flat and could prevent the chassis from sitting back in position. Once in position dress the leads of the decoder and carefully solder into position. This view shows the clips which hold the front of the chassis into the body. There is not a lot of room. It is important with this loco that the chassis fits correctly. I.e. no additional force required to refit the rear clip.