Recently I tried running a very large G scale train. Where ever there was a weak spot, the train would break apart. Some couplers are truck mounted and they'll dip down under pressure and uncouple. I was getting frustrated at them. I remembered when I ran my O scale two rail train, how heavy a load it was. As I was assembling it, I tried to move it by hand. Holly cow!! The thing weighed a ton!
So I tried this time to pull the G scale train. It was even heavier then I remember. I find it funny what we ask our engines to do. If I struggle to pull this, how can these engines do it? I make sure now that I have more than enough motive power pulling and even pushing a train. Some of these G scale engines have plastic gears inside. They won't tell you when they're overworked unless you're paying close attention. They won't call out your name and ask for help. They'll die trying to move it. Literally, they'll burn up or destroy themselves.
If you try and run long trains at your clubs or events, try it yourself. Try and pull the cars your asking your engines to pull. I think you'll be amazed at what a long train can take to pull up any grade at all. It maybe a scale model, but Boy, gravity still applies!!! Lend them a hand! Give them a helper! or....when they wear out, remember this and you'll know why.