I bought my son the Bachman Emmett Kelly, Jr. Circus train for Christmas. The coal car requires a 9 Volt battery but this size battery is just a little to big to fit into the battery compartment. The connection points inside the battery compartment are not the common male female connection points I'd expect but are just metal plates for contact. The picture on the inside of the battery compartment lid shows a standard 9 volt battery like the one I'm trying to squeeze in though if it went in I don't know what it would take to get it out. The coal car was made in China.

Can anyone tell me what I need to do so this will work? We are new to model rail roading. I chose the G scale because we are members of a club with a large outdoor g scale track for the children.