I have 2 Bachmann steam engines that I want to couple together. One is the 150 0-6-0 steam engine that comes with the Chattanooga train set. The other is the 0-6-0 steam engine 2126 of the tether. Both are running at the same speed. I cannot figure out how to the tether of either to hook to the front of either engine. Is there a part I am missing to do this. I notice that the c hook on the front of both engines are non moving but they look the same. Any ideas. Thanks.