Frequently Asked Questions (FAQs)
Below are frequently asked questions about the Purple Line organized into six categories. Select “+” next to each question to reveal the answer.
About the Purple Line
What is light rail?
Light-rail transit (LRT) is an electric railway system characterized by its ability to operate single cars or short trains along rights-of-way at ground level, on aerial structures, and in tunnels. LRT can operate in mixed traffic or in a separate right-of-way. The Purple Line will run in both mixed traffic and in a separate right-of-way.
What is the difference between light rail and metro?
Light rail is powered by an overhead catenary system and can operate on the surface of roadways where vehicles and pedestrians can easily cross over its tracks. As compared to light rail, heavy rail or Metrorail uses a third rail to operate and therefore, must be in an exclusive right-of-way that is grade separated from cars and pedestrians.
Where are the Purple Line stations located?
There are 21 stations – 10 in Montgomery County and 11 in Prince George’s County – all inside the Capital Beltway. For detailed information on station names and locations, please visit the stations page.
Why is the State of Maryland building the Purple Line?
The main purpose of the Purple Line is to:
- Provide faster, more direct, and more reliable east-west transit service connecting major activity centers in the corridor including Bethesda, Silver Spring, Takoma/Langley Park, College Park/University of Maryland, and New Carrollton.
- Provide better connections to existing Metrorail and MARC commuter rail services.
- Improve mobility and connectivity to the communities in the corridor located between existing rail lines.
What is the Art-in-Transit Program?
The Art-in-Transit program recognizes public art as an integral element of the transit project and further enhances the Purple Line’s high-quality stations, aesthetic treatments and landscape designs. Art will be incorporated into stations as well as certain other project structures including bridges, fencing, and lighting.
What is a Community Advisory Team (CAT)?
CATs are member-driven teams with representatives appointed from neighborhood and civic associations adjacent to the alignment. There are also representatives from business associations and local governments. There are a total of eight CATs – four in each county. Learn more about the Purple Line CATs.
Schedule
Construction
How can I stay informed of Purple Line construction scheduled in my area?
Sign up to receive updates in English or Spanish via email, text, or both. You also can visit the project website to learn about information provided to each CAT group in past meetings.
What is test pitting?
Test pitting is a minimally invasive excavation method used to investigate subsurface conditions, often completed prior to commencement of construction activities. Crews will dig multiple (often small) holes as a survey method to visually identify utility locations and other subsurface conditions.
What are the construction work hours?
Typical construction work hours are 7 a.m. to 7 p.m. Monday-Friday throughout the project. In certain areas, work may occur at night or over a weekend on an as-needed basis. The public will be notified in advance for any work that would occur during night and weekend work.
How is construction noise being mitigated?
Construction noise is mitigated through the use of noise and vibration monitoring equipment located in various sensitive areas along the project alignment. This equipment is monitored reported monthly to Maryland Department of Transportation Maryland Transit Administration (MDOT MTA) to verify compliance with the project requirements.
How is dust and air pollution related to construction being mitigated?
The Purple Line takes a mitigation approach to emissions that begins at the source and will only purchase, rent, or utilize off-road equipment that meets the various emissions requirements established by Maryland law. By only utilizing compliant equipment, the project is operating within the requirements. In addition, idling of delivery, dump trucks, and other diesel-powered equipment is limited to three minutes. Dust is monitored by environmental personnel who are certified in EPA Method 9 for visible opacity. This process evaluates any dust clouds generated inside and outside the jobsite. Project requirements dictate that dust opacity cannot exceed 15% at the project boundary.
Have environmental studies been conducted?
Yes, prior to the beginning of design and construction, the Purple Line conducted environmental impact studies and documentation required by the Federal Transit Administration (FTA) including mitigation plans.
How is the Purple Line helping businesses along the alignment that may be impacted by construction?
The Purple Line is working with local businesses and chambers of commerce to avoid and minimize disruption to their operation during construction. The Purple Line team also works to utilize local businesses for project needs, creating "Open for Business During Construction" signage for businesses along the alignment, and providing resources and counsel.
What is “blasting” and how does it work?
Blasting is the controlled use of explosives or gas pressure blasting pyrotechnics to break rock for excavation. The Purple Line will only use controlled blasting when the rock conditions require it. Explosives are not kept on site, but rather transported from West Virginia to the blasting site the day blasting is scheduled. The Purple Line will notify residents that have signed up to receive electronic construction notifications 24 hours before blasting occurs at the Plymouth Tunnel, and 72 hours before blasting occurs at the Bethesda Shaft.
Will existing bicycle and pedestrian trails be affected by construction?
Yes, some existing bicycle and pedestrian trails will be affected by construction. The Purple Line team is coordinating with Montgomery County and Prince George’s County to minimize impacts to these trails and establish detours where needed. View the current list of Construction Detours.
Are bicycle and pedestrian improvements part of the project?
Yes, there are several trails and bike lanes that will be built as part of the project. Visit here for more information on the trails.
What are the noise levels that Purple Line construction cannot exceed?
| Times | Weekday Residential Zone | Weekday Non-Residential Zone | Weekends Residential Zone | Weekends Non-Residential Zone |
|---|---|---|---|---|
| 7:00 a.m. to 9:00 a.m. | 85 | 85 | 55* | 62* |
| 9:00 a.m. to 7:00 p.m. | 85 | 85 | 65* | 67* |
| 7:00 p.m. to 10:00 p.m. | 65* | 67* | 65* | 67* |
| 10:00 p.m. to 7:00 a.m. | 55* | 62* | 55* | 62* |
Why did the entire Capital Crescent Trail need to be closed for the full duration of construction?
Most of the Interim Georgetown Branch Trail between Bethesda and Silver Spring Metro is located within the same right of way where the Purple Line tracks are being built. For safety reasons, the entire right of way where the Interim Trail exists must be closed due to the type of construction that is taking place and since the trail is located in the same construction work zone.
How does construction affect bus routes in Montgomery and Prince George’s counties?
As construction progresses, some bus routes and bus stops in Montgomery and Prince George’s counties will be affected. The Purple Line team is coordinating with WMATA, The Bus, Ride-On, and the University of Maryland Shuttle to minimize impacts and notify riders well in advance of any route changes.
Operations
How large is a Purple Line train? How does it compare to a Metro train?
The train itself is 5 modular light rail vehicle spanning 140 feet, as opposed to a single 75-foot Metro train. Additional details about the train can be found here.
What are the noise thresholds that Purple Line trains must operation within?
The average noise levels emanating from the Purple Line light rail vehicle (LRV) shall not exceed the levels indicated below for non-corrugated, tangent track with all auxiliary equipment operating simultaneously. Special wheel profiles, wheel dampers, and/or other noise mitigation measures shall be provided on LRVs to ensure that wheel squeal in curves does not exceed 78 dBA. Noticeable pure tones are not permitted. The table below details the noise limit of the LRV.
| Exterior Noise Limits | |
|---|---|
| Condition | Noise Limit |
| LRV Stationary, Full HVAC | 68 dBA |
| LRV Moving, Empty, Full HVAC on Horizontal Tangent Track at 40 mph [65 km/h]9:00 am to 7:00 pm | 75 dBA |
| In Maximum Dynamic Braking or Maximum Friction Braking from 40 mph [65 km/h] with New Wheels | 75 dBA |
Will current bus routes and bus stops change when the Purple Line is built?
Any changes to existing bus routes are decisions that would be made by the individual bus operators, including WMATA Metrobus, Prince George’s County TheBus, Montgomery County Ride-On, and the University of Maryland Shuttle. The Purple Line team conducts meetings with the bus operators to coordinate any temporary bus stop relocations and route adjustments that are required during ongoing Purple Line construction.