Electricless Gravity Escalator
Escalators are very popular and convenient but consume a great deal of electricity. Majority of escalators are running most of the time even without any riders.
The idea is to harness the body weight of riders to operate the down escalators. As soon as a passenger steps on the escalator, it will move down using its gravity. It will need a controller to keep the speed constant. The best way is to convert existing escalators so there is no need to replace them. It should not take long for a team of competent engineers to figure it out.
It will save half of the cost of electricity used for escalators which can run into billions of dollars every year. They should be also be much cheaper to make and maintain as no motors will be needed. Any engineer interested in this idea? You can make a fortune and help save the earth!