After a lengthy diversion in the downtown core last year, the 501 Queen streetcar route will once again see a long-term service disruption in 2017.

Starting today, buses will be replacing streetcars on the route west of Roncesvalle Avenue along The Queensway and Lake Shore Boulevard due to bridge work as well as road and track improvements.

The following service changes begin Jan. 8:

• 501/301 Queen streetcars will run between Roncesvalles Avenue, downtown, and Neville Park Loop.

• 501L/301L Queen buses will run between Dufferin Street (Dufferin Gate Loop) and Long Branch Loop, via Queen Street, The Queensway, Windermere Avenue, and Lake Shore Boulevard.

• 501M Queen will run a clockwise service linking The Queensway with Lake Shore Boulevard, Marine Parade Drive, and Park Lawn Road.

The TTC says riders can transfer between streetcars and buses between Dufferin Street and Roncesvalles Avenue but PRESTO users are asked not to tap when they board the second vehicle.

The TTC has not said when regular streetcar service is expected to resume.

The service disruption comes after 501 streetcars were forced to divert for several months along Queen Street due to construction work between Bathurst Street and Spadina Avenue last year.