Dave,
Yes sir, what I found was that I was removing the wrong screws. On the cars I have there are four screws ... one under the coupler arms at each end of the car (which are the ones I was initially removing) and one closer to the trucks. The pair to remove are the ones closer to each truck. Once I removed the correct screws the top did pop right off and I was able to clean the cars and add passengers.
Hope this helps.
bd
