I have purchased Item number 44548 and item number 44549 and 44947 thinking I could make a reversing trolley with these items. Am I wrong and do I need to buy anything different to create my trolley to be reversing. Please help.

I am new and have set up some trains in my basement for my grandkids. They are not here often but they love trains and when they come over they will love to look at them and watch them run. I have bought two starter sets but now want to get a more powerful engine to pull several box cars up a pier set. the two engines I have will pull two cars and a caboose but if I add more they struggle to get up the hill. Any help would be appreciated.