I just got my Scale Trains Big blow Turbine in N Scale and I find the fuel tender doesn’t want to roll freely. There seems to be a lot of resistance, if one was to give it a good push on a straight stretch of track it wouldn’t go more than 2-3 inches before it comes to a dead stop. All the wheels are in gauge I checked. Has anyone opened one of these up and added weight? Does adding a tiny drop of oil on the axle points help?