If you live in a city that has a subway, you probably don't have a high opinion of the transit system.
Subways are often crowded, dirty, and the temperature uncomfortable.
Considering your opinion of the underground, think of how the people who work there must feel. According to the Scandanavian Journal of Work and Environmental Health , being a subway driver is a risky occupation. Compared to passengers who rode the subway every day, subway drivers had four times the risk of developing sciatica pain, three times the risk of hearing loss and twice the risk of stomach problems. The sciatica and hearing problems stemmed from the constant noise and vibration on the job, combined with poorly designed seats. No one's ever determined exactly why subway motormen have stomach problems.