​The TTC has approved a new 514 Cherry streetcar route set to run from Cherry Street along King Street in the east to Dufferin Street in the west — to bring relief to one of the busiest transit lines in the city,

The new route will operate in conjunction with the existing 504 King streetcar and service is set to begin in June.

Initial plans were for the 514 to be fully serviced by the new-model low-floor streetcars, making it the first accessible east-west surface line between Wellesley and Queen's Quay. But on Wednesday, TTC spokesperson Brad Ross said the fleet servicing the new route will be made up of a mix of old and new vehicles.

The 514 Cherry was approved by the <a href="https://twitter.com/hashtag/TTC?src=hash">#TTC</a> board today. Service starts in June with a mixed fleet of old and new streetcars for relief on King —@bradTTC

Last week, Ross told CBC News the city is set to receive four new streetcars per month beginning in April. Those streetcars were to be be put into service on the new Cherry route, as well as the Spadina, Harbourfront and Bathurst lines.

On Thursday, the TTC board considered whether to approve a $34 million plan to keep older streetcars running, pending the delivery of new-model streetcars from Bombardier.

Fifty-five new streetcars were expected to be operational in Toronto by the end of 2015. To date, just 16 have been delivered.

TTC board chair Josh Colle said Thursday that Bombardier's delays leave the TTC no choice but to upgrade old streetcars to "bridge the gap" in service.

Colle added that the city isn't ruling out legal action against Bombardier that would recover the millions that would have to be spent in upgrades.