Poor pullina Lnl 726

Maybe it is a 226E?  Does not sound like a 726. To get smoke you need to go to a 1947 or later 726. Or to also add magni-traction go to a 736. 

We might be able to help but your post (and the title) are a little confusing.  Maybe you could post a well-lit video, including some closeups of the loco, and what it's doing.  Thanks!

Oops, should have typed 226E. Anyway, runs faster backwards than forwards. Searched through the forum and now will check out the thrust washers.  Will get back on as needed. So amazing to enter a problem and get help. Thank you.

The 226E is a parallel plate motor.  I doubt your problem is a thrust washer. I would check to see how much wear there is in the various bushings including the axle bushings. Also check the condition of the commutator and brushes. If nothing jumps out at you, trying running it without the side and drive rods. Could be a wheel loose on the axle allowing the wheel to get out of quarter a little.