the older Lionel used E units to change the direction of the ac motor. to reverse a ac motor you have to change the field coif In relation to the armature winding. I suspect you have a bad e unit and they can be replaced and or repairs all the parts are available! send us some pictures when you take the engine apart so someone here on the forum can help you!
f:0" target="_blank">https://www.ebay.com/itm/LIONE...318!US!-1:rk:12f:0
f:0" target="_blank">https://www.ebay.com/itm/Lione...wkBZZpYZH:rk:29f:0
these are not the exact parts you need depends what you Lionel engine number is just tying to give you an idea what they look like!
check out the eBay web sight!