Don't worry, it's not just your Emily, she's deemed as one of the worst haulers. Even when she has the back wheel of her front bogie as an extra motorized wheel too. The only way you're really going to be able to get around that is to look into putting a traction tire on that back front bogie wheel I mentioned.
There's also this item called "Bullfrog Snot", it's a little jar of liquidy goo, and you just apply it to the tyre of an engine, supposedly giving it improved traction. I heard it works really well, but I've never used it myself.
There's also this item called "Bullfrog Snot", it's a little jar of liquidy goo, and you just apply it to the tyre of an engine, supposedly giving it improved traction. I heard it works really well, but I've never used it myself.