MTH Passenger Car Access

I recently picked up some older MTH heavyweight passenger cars in the 6240 series and would like to open them so I can place some passengers inside. But I can’t figure out how to access the inside of the cars. There are two screws underneath, but removing them loosens nothing. (These cars do not have four screws in the corners as do some newer models.) There must be a way to open things up, if for no other reason than to change the occasional light bulb. Do you simply pry the roof off? I don’t want to attempt that without some advice. Any suggestions will be appreciated.

John Gottcent

with my heavy weight cars its necessary to turn the trucks. The screws are only accessible with the trucks turned as they are located under them

My Railking heavyweights have a small screw above the drawbar and a larger one inside the car just under the roof and accessible through a hole in the floor.