Subway cars and stations can provide recycling containers alongside their trash receptacles to help encourage recycling. Subway operators can supply one or two bins for recycling items commonly used during travel, such as beverage containers and newspapers. In regions with bottle deposit laws, the subway system can obtain extra funds by recycling soda and juice cans. An alternative most subway stations in New York use is to separate recyclables from general trash after collection.
Due to the lack of sunlight, underground trains and stations must provide ample lighting for employees and passengers. However, it's possible to make subway lighting more eco-friendly by using efficient bulbs and turning off unnecessary lights. The subway system in Washington, D.C. began using LED (light emitting diode) bulbs in 2007 to light its stations. Such eco-friendly bulbs use less electricity and don't require replacement as often as incandescent or fluorescent types. Trains that also travel above ground can turn off some interior lights during the day.
Subway systems usually run on electricity, giving operators the potential to power them using eco-friendly renewable energy without modifying the train cars. A subway powered with solar, hydroelectric or geothermal energy would generate no emissions. If a city or country specifically devotes renewable energy to running its entire subway system, it can promote use of the underground as an eco-friendly "zero emission" transportation method. The city of Bilbao, Spain, for example, set up its subway system to run entirely on clean energy and power recovered from the use of train brakes.
As with any vehicle, it's important to consider not only the environmental impact of operating a subway train but the effects of manufacturing it in the first place. Manufacturers can produce such equipment in a more eco-friendly manner by using renewable energy sources and working with recycled materials when possible. This will also save energy and decrease transportation-related emissions if manufacturers locate factories close to cities that purchase subway cars.
