I think it is better to call 911 and not the Blueline taxi. I have taken a lot of blueline taxi due to work related stuff. The drivers are not so polite. They do not show up quickly. In your case, if you feel it is really the time that you are going to deliver your baby, by all means, call the 911. I have a friend who called 911 (she was in ottawa by herself) and it was very quick. It is so painful to deliver a baby, you will not have the energy to wait for the taxi and deal with the taxi driver.
Good luck!