After a durability test up to 750,000 km of train running, lubricants used at running parts of electric cars were sampled and analyzed. Gear oils, axle bearing greases and traction motor greases were apt to degradate gradually as the train running increased, but the degrees of their degradation were still within the allowable limits. The degrees of degradation of high-grade compressor oils and motor-generator bearing greases used fell within the limits, even though those of some low-grade oils and greases were exceeded the limits. Therefore, the inspection period for electric cars from the lubricating point of view will be able to be extended to about 600,000 km of train running.