Heavy Rail Rapid Transit ('L', Subway)
Quick Facts
- Setting: Medium-to-dense urban
- Station spacing: 1/4 to 2 mi
- Avg. effective speed: 20-45 mph
- Vehicle capacity: 80-120 passengers per car, train lengths up to 12 cars
- Upper ability: 40,000 passengers per hour
- Typical daytime frequency: 2 to 12 minutes
Overview
Heavy Rail Rapid Transit, often referred to generically as a "Subway" or "Metro," is a historically-proven and widespread method for moving large numbers of people quickly through urban settings.
Rapid transit systems typically have stations spaced between 1/4 mi. to 1 mi. apart, with some outskirts stretches with station spacing up to 2 miles. They use separated rights-of-way, so they can travel unimpeded quickly through cities.
Rapid transit serves urban needs over larger distances through medium-to-high density areas. These systems connect neighborhoods and business districts and often include several routes that span the reaches of a city's primary population area. Riders served by rapid transit are generally travelling from one neighborhood or urban district to another.
Trains on rapid transit can be as long as 12 cars on some systems, and carry as many as 1200 people on a single train.
This mode of transit exists in many forms and is currently built over various infrastructures--subways, elevated lines, and open-cut or otherwise grade-separated rights-of-way.
History
Early rapid transit dates to the 1880s, where cities like New York began to construct elevated railways. Early lines often used wooden trailer cars for passengers towed by coal-burning steam engines.
In the 1890s, Frank J. Sprague developed a technology that would allow motors under multiple train cars and by 1900, rapid transit lines in Chicago were using electricity as its locomotive power, with motors under each car. Quickly, this technology was adopted on transit systems around the world wishing to operate more than one vehicle at a time, with clean, efficient electric power--and it's still widely in use today.
Over time, transit technology developed to improve efficiency, capacity, and meet the needs of modern cities. Improved propulsion technology, communication and signaling systems, and modern amenities for passenger comfort and safety keep rapid transit a viable option for new transit today.
In New York, transit lines are beginning conversion to what's called "Positive Train Control," where trains are operated safely by computers, which can keep trains spaced safely.
Examples
Rapid Transit exists in dozens of cities around the world today, including famed systems in New York, Chicago, and London. It is a reliable, proven, heavily-used type of transit, that moves masses of people through cities with ease.
In many places, trains run as closely as a minute apart, and during off-peak, can run closely together.
Cities in the United States with rapid transit include (links to agency Web sites):
- New York, NY (MTA NYC Subway, PANYNJ PATH train)
- Chicago, IL (CTA "L" System)
- Washington, DC (WMATA DC Metro)
- Philadelphia, PA (SEPTA)
- San Francisco, CA (BART: Bay Area Rapid Transit)
- Los Angeles, CA (LAMTA)
- Boston, MA (MBTA "T")
- Atlanta, GA (MARTA)
Some rapid transit systems around the world (links to agency Web sites):
Considerations
- Is most effective in dense, urban areas, with strong ridership sources and centralized destinations
- Can efficiently serve medium-density areas and closer-in suburbs as well
- Electric transit results in no "local" pollution
- Generally requires private, separated right-of-way
- Requires significant investment to construct, including infrastructure (often built as subway to abate sound and keep infrastructure out of sight or to avoid land acquisition)
- Needs high ridership potential to justify expense of construction
Related Technologies
- Light rail (uses smaller-capacity, lighter-weight vehicles and often shares rights of way with auto traffic)
- Commuter rail (operates over larger distances in lower density areas with wider station spacing)