Don't know what run the NH s-2 I have is but it runs smoothly and continuously around my layout. Ever since I bought it. It had problems at first because I hadn't cleaned the track for a while, so I did that, and I ran it on alcohol-soaked paper towel a little but now no stalls on switches or crossings. Maybe run yours on the alcohol wheel scrub track and see if that helps. It's quite cute puttering around the layout sounding like a washing machine. I hope to have a PA with sound someday to join in the noise making. Wondering about getting a sound-equipped FA, hmmmmm. Don't think you can get a sound unit into an RS-3, tho. The NH was nutso for Alcos.