A popular Yule tradition is running electric trains under the Yule Tree, as a decoration. Countless households bring out the old train set for the occasion. After a year in storage, usually in an attic, closet or basement, the trains are given another year's workout. The old train set has endured heat, humidity, and the exigencies of storage since last Yule.
Folks expect it to run as usual year after year.
Consider the fact that most of the household Yule sets are pretty old. They have been handed down to another generation as a Yule tradition. Along with adorning the Tree, they've endured the play of children year after year. Most people expect the trains to run well every year. No thought is given to wear and tear, corrosion or problems of age and un-use.