@Train Nut posted:Plastic trucks - no oil.
Metal trucks - A drop of oil on each wheel.
By plastic, I assume you mean the needle point axles- plastic journal boxes and metal wheels and axles. No oil on those. For post and prewar I put a dab on the inside of each wheel where it meets the axle and spin them until they spin freely. They can get gunked up over the years and create a lot of drag in a consist of any length.