Hawthorne Village trains won't stay coupled

My father just passed away and I inhereted 4 train sets, 2 mid-50s Lionels (they will get their own post) and these two which were new in the boxes, never assembled (he was a huge Wings fan):
http://www.collectiblestoday.com/ct/product/prdid-49222.jsp

http://www.collectiblestoday.com/ct/product/prdid-917245.jsp?red+wings&endeca=true

I have a few problems, 1 is they won't stay coupled, the track is flat and connected properly, the manual says just bump them together and they will connect, but the connections seem really loose and some of them you have to move around to connect. The heavy cars have the little spring on the coupler (like this http://www.litchfieldstation.com/xcart/images/T/380-148-2.jpg), but the lighter cars do not, they are the ones that come uncoupled. Does the big curved plastic part do anything or have an adjustment?

2 is the second engine car on both sets does not move on its own, the engine doesn't work, it just sits there without the main engine pulling it, are they both broken, or do I have to do something to get it to work?