I’ve recently been focused on cleaning all of the track on my layout. Prior to that, I hadn’t noticed any performance concerns, but the cleaning was probably overdue. After I cleaned it, I ran a new steam engine around 2 loops and it performed well. However, I then added a consist of 6 MTH premier passenger cars and sent it up a roughly 2.2% grade. It got halfway up and the steamer’s wheels began to spin as it lost traction. It was moving at 25 scale mph. After I backed it back down, I tried it again going at 40 wondering if momentum would carry it - yes it went further, but with the same ultimate result - I expected that but I thought I’d give it a shot. My first thought was to inspect the engine and it’s traction tires and they looked fine. I also wondered if maybe the suspension caused those wheels to have poor contact with the rails but all looked well. I then combined the consist with another steamer that I had usually paired with it and which traditionally had no problems pulling it up the grade. Sure enough, this engine began to slip as well. I took a rag and ran it across the rails and it came back clean and dry, that is, no dirt and no sign of any grease or lubricant of any sort — so maybe too clean?
I had used WD-40 contact cleaner (not the lubricant) to clean the track which I had on hand and which I had seen as recommended in another thread several months back. I’m wondering if it polished the rails too well. The layout is a combo of Ross and Gargraves. My ultimate solution was to take a sanding block to rough up the rails and sure enough, both engines and the consist once again made it up the grade without too much concern. I had to go back and do an additional rough up on the rails in some spots where I did see some continuing slippage. I just thought I’d share this with you all. Btw, I did not have any concerns when the train ran on a flat surface. The loss of traction on an incline was the concern.