Hi folks...I have a Bachmann 2-6-2 that has a pulling problem. Even though my rolling stock is not all weighted per NMRA standards, this engine IMO should be able to pull more than 4 cars up a 2% grade. Instead. I get a lot of wheel slippage and need to use the ole 5 finger helper engine to get it to the top. Not very realistic! . Any suggestions? Thanks, Matt--Hershey, Pa.