Depends.
Transit differs from car based transportation because as use increases average speed doesn't change, average speed actually tends to increase due to increased frequencies. This means that there is little to no latent demand as capacity is easily increased to meet demand. Transit can usually build capacity with demand, up until a certain point. Line 1 is starting to reach its "maximum", requiring big money to upgrade it.
The streetcar network hasn't had a capacity increase since the early 1990's, despite the extreme growth pressures placed on it. It's ridership has plateaued at around 250,000 daily trips, the maximum capacity of the system. The new streetcars will boost network capacity by roughly 30%, most of which will get eaten up by latent demand, which has built up over the last 20 years as there has been no capacity increases (actually a net decrease since the 1980's). Thats why the additional order of 60 new streetcars is so key, to go beyond the latent demand recuperation and to deal with ridership growth of the next few decades and to get streetcar crowding standards down, which is where you will actually see an improvement in quality of service.