Arnold,
I agree with you 100% about lubricating those postwar wheels when pulling long trains. Makes a huge difference. I've found that without fresh lubrication the cars will pull off the tracks (towards the inside of the curve).
I've also found that synthetic oils provide longer service between lubrications. I like "Liquid Bearings" brand but I know that there are others.
Also, on long trains, heavier cars towards the front, lighter in the rear.