Light rail trains are running on energized tracks between Lyttonsville and Bethesda for the first time, bringing the long-delayed Purple Line a step closer to giving Potomac commuters a new transit connection without driving into downtown Washington.

The Maryland Transit Administration announced in its July outreach newsletter that live wire testing advanced into Montgomery County in late July, with the 16-mile project now more than 90% complete. The milestone marks the first time Purple Line trains have operated under power in the county.

"This month, light rail vehicle live wire testing has advanced all the way to Bethesda, another step towards the critical trial running phase planned for 2027 and certifying the system for operations," Purple Line senior project director Ray Biggs II wrote in the July newsletter.

What it means for Potomac

Bethesda station will be the Purple Line's western terminus and the closest stop to Potomac. Riders along the River Road corridor will be able to connect to the Metro Red Line there, and the Purple Line itself will link five Metro subway lines, three MARC commuter rail lines and Amtrak service between Bethesda and New Carrollton without routing through D.C.

The station will be accessible by foot from Woodmont Avenue and by elevator or escalator from Wisconsin Avenue, according to WMATA planning documents. Construction required crews to build a 150-foot-deep shaft between two new buildings to create the elevator connection to the existing Metro station below.

Testing details

All 1,187 overhead wire poles have been installed along the 21-station route. Train operators are testing acceleration and braking at varying speeds and periodically sounding the horn and bell. Testing initially ran overnight from 9 p.m. to 5 a.m. and has since expanded to weekdays from 7 a.m. to 7 p.m.

The overhead power lines are now energized. MTA officials warn the public never to walk on the tracks or station platforms in the testing area.

Timeline and cost

The Purple Line was originally scheduled to open in March 2022. It is now more than five and a half years behind schedule. MTA says passenger service will begin in late December 2027, though financial documents reported by 7News indicate a projected opening of Jan. 6, 2028.

The total project cost, including a 30-year operations and maintenance contract with Purple Line Transit Partners, has climbed to an estimated $9.5 billion as of a September 2025 Bethesda Magazine report. That is nearly $4 billion more than the original price.

Once running, the 142-foot-long rail cars will carry up to 430 passengers each and arrive every 7.5 minutes at peak hours, with an end-to-end travel time of 63 minutes.

A trial running phase must be completed in 2027 before the system can be certified for passenger operations. No public comment period is tied to the current testing phase.