Light-emitting diode (LED) technology has caught the eye of Washington Metropolitan Area Transit Authority (WMATA) officials, who have been searching for ways to improve lighting at Washington, D.C., area Metrorail stations. Incandescent, fluorescent, and mercury vapor lamps originally illuminated the rail system, which opened in March 1976. Today, the main light sources are fluorescent, metal halide, and high-pressure sodium lamps, and in May 2007, WMATA initiated a pilot project using LED fixtures for platform lighting at the Foggy Bottom/George Washington University station.
Ed Riley, manager of architecture for WMATA, explains that lighting the stations always has been a challenge. While the transit authority wants to update the system's lighting scheme, Riley says, “The cost will be quite a bit, you're talking about introducing a new infrastructure into the stations.” Although funds currently are not available, WMATA energy management engineer Do Yee says they always are looking at new lighting technology. One example is the Foggy Bottom pilot project that was part of the Infrastructure Renewal Program (IRP), which exists to replace or upgrade the physical assets of the Metro according to industry standards. For the pilot project, WMATA selected LED Folio's TiLux, which features a slim, square profile and a die-cast aluminum housing. To illuminate the platform, 48 fixtures were installed with a color temperature of 5600K, but in future installations, Yee says a warmer color temperature would be used. Some customers say the LEDs at Foggy Bottom are too bright, but Riley mainly attributes that to the fact that only the platform lighting in the station was switched to LEDs.
WMATA has updated its design criteria, which will apply to future projects and result in higher light levels (currently, platform light levels are 3 to 5 footcandles). But the greater challenge is upgrading existing stations without disrupting train service. A design feature unique to D.C.'s Metro system, according to Riley, is the placement of light fixtures on the track bed. However, the design criteria no longer permits fixtures that require track access for maintenance. “A solution to mitigate the issue of track bed lights in the existing underground stations is desired,” Riley says, “but a solution for this has yet to be funded and designed.” Funding to make the lighting “compatible and sensitive with the architecture yet...economical, energy efficient, and easily maintainable” likely will be budgeted as part of the IRP, Riley says. “Our plan...is to have an architectural and lighting design firm come up with a concept to improve maintenance access to lighting. We've started that, but it goes in spurts depending on availability of funding.”