The Colesville Road Line, designated as the Colesville Road–Burtonsville Line on Route M52, and Colesville Road–Greencastle Line on Route M54, are daily bus routes operated by the Washington Metropolitan Area Transit Authority between Burtonsville Crossing Park & Ride lot (M52) and Greencastle Park & Ride Lot (M54), and Silver Spring station of the Red Line of the Washington Metro. Both lines operate every 30 minutes at all times, at a combined frequency of every 15 minutes. Both trips are roughly 60 minutes long. These new routes replaced the Silver Spring–Fairland Line routes Z6 and Z8, and Laurel–Burtonsville Express Line route Z7 as part of WMATA's Better Bus Network Redesign on June 29, 2025.
Background
Route M52 operates daily running between Silver Spring station and Burtonsville Crossing Park & Ride with select weekday peak hour trips extended to South Laurel Park & Ride. The route operates via Calverton, Westfarm, and White Oak, Maryland.
Route M54 operates daily running between Silver Spring station and Greencastle Park & Ride mostly along Old Columbia Pike and Colesville Road.
Both Routes operate out of Montgomery division.
History 20th Century
Route Z2 originally operated as the Silver Spring-Wheaton Line under the Capital Transit Company. The line originally operated between Silver Spring and Wheaton Metro stations. The line was transferred to buses in the 1940s but was later discontinued.
The Colesville–Ashton Line was originally operated under route Z1 which operated as Streetcars. The line was later formed by buses in June 1956, renamed to route Z2, and acquired by DC Transit. The line was later acquired by WMATA on February 4, 1973.
Route Z2 operated alongside the Z1, Z3, and Z4 as the Colesville Line. Route Z2 operated between Silver Spring Metro station and Olney with select trips ending in Cloverly.
On February 19, 1978, route Z2 alongside the Z1, Z3, and Z4 was extended to Silver Spring Metro station after it opened on February 6, 1978.
Route Z6 was created on January 27, 1985, which operated between Silver Spring station and Calverton mostly operating along Calverton Boulevard, Old Columbia Pike, Columbia Pike, Lockwood Drive, Colesville Road. In the 1990s, route Z6 was discontinued and replaced by route Z7 which took over the Calverton routing which Z6 operated on.
Route Z7 was also created on January 27, 1985, which operated between Silver Spring station and Burtonsville Crossing Park & Ride lot alongside route Z6 which operated to Calverton instead of Burtonsville. In the 1990s, Z7 was rerouted to operate under the Calverton Express Line alongside route Z17 replacing route Z6. Route Z7 and Z17 operated along Colesville Road, Columbia Pike, and Beltsville Drive with route Z7 diverting onto Colesville Road between Burtonsville Park & Ride and Columbia Pike and Industrial Parkway while route Z17 remaining on Columbia Pike. A route Z19 was later introduced to operate between Silver Spring station and the Seventh-day Adventist Church Parking Lot via Takoma station having a single trip operate in both directions during the weekday peak hours. The route was later discontinued on June 29, 2003, due to low ridership.
Route Z8 had prior incarnations as the Old Bladensburg Road Line and the Sligo Avenue Line. The lines were at first operated as streetcars under the Capital Traction Company. The lines would later be operated by buses in 1927 and 1940. Both lines were later merged into one, later operated until DC Transit in 1956 and then acquired by WMATA on February 4, 1973. However the Z8 was later replaced by Ride On.
Route Z8 would later be reincarnated as the Colesville Road–Fairland Line which would operate between Silver Spring station and Burtonsville Crossing Park & Ride lot via White Oak, Greencastle Park & Ride Lot, Briggs Chaney Park & Ride Lot, and a few peak-hour trips to Verizon–Chesapeake Complex.
Routes Z9 and Z29 operate as part of the Laurel–Burtonsville Express Line operating between today current route between Silver Spring station and South Laurel Park & Ride Lot. The major difference between routes Z9 and Z29 was route Z29 remained on Columbia Pike while route Z9 was rerouted along Colesville Road between Burtonsville Park & Ride and Columbia Pike and Industrial Parkway.
Routes Z1, Z3, and Z4 were separated from the Colesville Line and got formed into different routes by the 1990s. Routes Z1 and Z4 were formed into the Glenmont–Silver Spring Line to operate between Silver Spring and Glenmont Metro stations. Routes Z3 and Z5 operated between Silver Spring Metro station and Burtonsville Park and Ride. Route Z2 remained under the Colesville Line being extended to Olney (Spartan Road & Georgia Avenue).
In September 1993, Ride On took over the Saturday service for the Z2, under the Colesville–Silver Spring Line. The reason why was because WMATA had to reduce costs and apply buses to more higher ridership routes.
21st Century After a series of proposals in early 2004, many changes happened on the Colesville Road Line.
Route Z2 was rerouted to serve Briggs Chaney, Good Hope, and Cape May roads instead of operating directly via New Hampshire Avenue and replacing route Z3. Weekday, midday, and Saturday trips only operated between Silver Spring Metro station and Colesville. Route Z2 would be renamed to the Colesville–Ashton Line as a result of the changes.
Route Z6 was also reincarnated in service as the Tanglewood–Westfarm Line, which would operate between Silver Spring station and Burtonsville Crossing Park & Ride lot via Calverton, Westfarm, and White Oak, Maryland on September 26, 2004. The new Z6 replaced the Glenmont–Silver Spring Line (Z1 and Z4), Colesville–Fairland Express Line (Z3 and Z5), the Calverton Express Line (Z7 and Z17), and route Z8's routing between Greencastle Park & Ride Lot and Burtonsville Park & Ride.
Route Z6 replaced route Z4 routing between Lockwood Drive, Stewart Lane, and Old Columbia Pike through the White Oak Shopping Center and White Oak Apartments, Z1, Z4, Z5, Z7, & Z17's routing on Columbia Pike, Industrial Parkway, Tech Road, and Broadbirch Drive in Westfarm, and a portion of Z7 & Z17's routing on Calverton Boulevard in Calverton. Routes Z1, Z3, Z4, Z5, Z7, and Z17 were all discontinued and route Z8 was shorten to Greencastle Park & Ride Lot with all the discontinued routings combined into the new route Z6. Route Z6 will operate along Lockwood Drive to White Oak, then operate to Calverton via Broadbirch Drive, Calverton Boulevard, Galway Drive, and Fairland Road. Route Z6 will then operate along Briggs Chaney Road serving Briggs Chaney Park & Ride and #14000 Castle Boulevard. It will then operate along Old Columbia Pike to Burtonsville Crossing Park & Ride lot. The service would only operate on weekdays however.
Route Z8 was also shorten to operate between Silver Spring station and Greencastle Park & Ride Lot via Briggs Chaney Park & Ride Lot on the same. Service to the Burtonsville Crossing Park & Ride Lot was replaced by new Route Z6. The Z8 also replaced portions of the Z1, Z3, Z4, and Z5 which were all discontinued on the same day. Route Z9 and Z29 also replaced portions of route Z7 and Z17 between Silver Spring and Industrial Parkway.
Later Changes On June 24, 2007, Route Z2 was rerouted to remain on New Hampshire Avenue between Briggs Chaney and Cape May roads. Service along Good Hope and Cape May roads got discontinued and replaced by Ride On Route 39. Route Z6 service to Tanglewood was discontinued and replaced by a new Ride On Route 21. The line was also changed from the Tanglewood–Westfarm Line to the Calverton–Westfarm Line.
On June 28, 2009, most off-peak service for route Z2 was discontinued due to low ridership. Weekday peak hour service and Saturday service still operated.
In 2012, WMATA proposed to eliminate all the Saturday Z2 service and on the four federal holidays on which a Saturday schedule is operated. This was due to unduplicated segment of the Saturday Z2 (between Bonifant Road / Good Hope and Randolph roads) that served very few passengers and most of the Saturday Z2 was served by another route with capacity to accommodate the 2012 route Z2 riders. Alternative service was provided by Routes C8 and Z8.
In December 2012, WMATA announced that all the weekend Z2 trips operated by Ride On will be eliminated on January 12, 2013 due to low ridership. Alternative service would be provided by routes C8 and Z8.
When the Paul S. Sarbanes Transit Center at Silver Spring station opened, Routes Z2, Z6, Z8, Z9, and Z29 were rerouted from its bus stop along Dixon Avenue to Bus Bay 113, Bus Bay 106, Bus Bay 114, and Bus Bay 112 respectively.
During WMATA's Fiscal Year of 2016, WMATA proposed to add Saturday service to route Z6 between Silver Spring, Calverton and Fairland with buses arriving every 30 minutes and to reduce the number of trips between Castle Boulevard and Burtonsville. WMATA reasons that the current route Z6 schedule does not provide enough time for buses to get from one end to the other, ridership is high for route Z6 on the weekdays, and there are very few riders using the Z6 between Castle Boulevard and Burtonsville.
Routes Z9 and Z29 were also proposed to be combined into one route into a new route Z29. However, route Z29 will divert onto Old Columbia Pike between Greencastle and Briggs Chaney Roads discontinuing a portion of the route along Columbia Pike. A new Route Z3 will provide off–peak direction bus service between Silver Spring, Burtonsville and South Laurel replacing route Z9. The express section of Columbia Pike, between Greencastle and Briggs Chaney roads would be eliminated.
On March 27, 2016, Saturday service was added for Route Z6 which will operate between Silver Spring station and #14000 Castle Boulevard only. Saturday service will operate every 30 minutes, the same as weekday frequency. Routes Z9 and Z29 were also discontinued and replaced by a new Route Z7. The new route would operate every 30 minutes along the former Route Z9 routing with express service along Columbia Pike between Industrial Parkway and Burtonsville Park & Ride. Route Z7 will operate during peak hours primarily in the peak direction with a few trips operating in the non peak direction and have the same boarding/alighting restrictions as Routes Z9 and Z29. Route Z7 will also have an increase frequency in South Laurel, which was something that wasn't provided by routes Z9 and Z29.
In 2016 during WMATA's 2017 Fiscal Year, it was proposed for route Z7 to eliminate service between Burtonsville Park & Ride and South Laurel with alternative service provided by routes 87, 89, and 89M. The reason was for WMATA to reduce costs and it was a high subsidy per rider. Another option was for route Z7 to be available at a reduced frequency and span. Other proposals was for route Z7 to be shorten around Fairland or Burtonsville Park & Ride discontinuing service to Silver Spring station with service replaced by Ride On Flash BRT U.S. Route 29 route when it opens.
On June 25, 2017, the frequency of buses from reduced from 30 minutes to 35–45 minutes for route Z7.
During WMATA's 2021 Fiscal Year, WMATA proposed to eliminate the Z6 route segment between Castle Boulevard and Burtonsville Park-and-Ride and replace it with the Ride On Flash BRT U.S. Route 29 route when it opens. However, Route Z6 will be extended to Greencastle Park and Ride replacing routes Z8 and Z11 and adding additional frequency to the Z6 and add new Sunday service. The reasons all come down due to the upcoming Ride On Flash BRT service along U.S. Route 29. As a result, WMATA would eliminate all Route Z2, Z8, and Z11 service as it was going to overlap the upcoming Ride On Flash BRT service along U.S. Route 29.