Riders on Toronto's busiest streetcar route are set to get some relief in the coming weeks.

Beginning January 1, the 504 King streetcar will become a proof-of-payment line, with passenger boarding allowed at all doors on individual cars. 

The new system will be in place from 7 a.m. to 7 p.m. daily. 

The often-packed Queen and Spadina streetcars are already under a similar regime.

TTC 504 King Streetcar

At 60,000 daily weekday riders, the 504 streetcar is the TTC's busiest surface route. (Canadian Press)

Mayor John Tory announced the changes this morning alongside TTC chair Josh Colle and TTC chief executive Andy Byford. 

Tory said the city estimates that as a result of the changes, the 504 King will spend about 50 per cent less time stopped to allow passengers to board. He added that "no mercy" will be given to fare evaders.

But some transit watchers are skeptical of this morning's announcement. 

"They may be overselling the benefit of this change because its already being done on an unofficial basis already," said Steve Munro, a prominent Toronto transit advocate and critic. 

In an interview with CBC's Metro Morning on Monday, Munro pointed out that due to overcrowding, many streetcar operators already allow passengers on the 504 to board at all doors. 

"To make it official will simply regularize a practice that a lot of operators already use."

But riders be warned — transfers will now serve as proof of payment, so if you paying for your ride with tokens or cash, be sure to grab your transfer regardless of if you need it. 

The 504 King is Toronto's busiest streetcar route, with about 60,000 riders boarding each day. 

In August, city staff submitted a report to council that found most delays on the city's streetcar routes were the result of inefficient passenger boarding procedures, resulting in increased commute times of between four and 15 minutes.

In October, a private company completed trial runs of a crowd-funded express-route bus, dubbed Line Six, that took passengers from transit-starved Liberty Village along King Street West to downtown for $5 per person. The effort is a direct result of commuter frustration with overcrowded streetcar routes.