from talking to people who work inside transit for 10 years plus this is what I can share,
when you go in as a person with experience and education BUT DIDNT take the test, you will have to take the test in order to become permanent , if you don't pass the test I believe you can take the test as much times as you can, BUT keep in mind for those who pass the test will have more seniority over you and basically you will be at the bottom of the barrel , MTA tells you these things so they can cover them selves so incase there is a layoff the TEMPS aka Provisional will be layed off first.....DONT fear , just do your job and keep low from the radar , as stated people been on this job for 10 years plus and never passed the test, there still TEMP aka Provisionals
as for passing the test, you will get a list#. For example..i took the Signal Maintainer practical in April and got a letter before the list was even established which was in Oct. 2017, not even 1 year passed, even though I passed the practical my paper states TEMP on it because the list hasn't been established as yet and then when it does I will have to wait for them to reach my list# so on and all this will be basically 2+ years for me to become permanent and DONT forget probation is another 1 year