Becoming a motorperson for the T

I was in Boston recently and first of all, let me just say that you have a great transit system and a beautiful city. Each city that has a subway system has something unique about it, and Boston is certainly no exception. Light rail cars that run on elevated structures, in the subway, trains that switch from pantograph to third rail (and uncovered third rail at that - the only other city that I know does that is Chicago), just to name a few.
I however, am curious as to how one becomes a motorperson for the T. I know that there is a job lottery held every couple of years, and those who apply and get selected from the lottery get hired. My question is - in order to become a motorperson, does one have to be a guard, bus operator, or light rail operator first, or can you go straight to motorperson?
One other question - when becoming a motorperson (or guard for that matter) do they get qualified on the red, blue, and orange lines, or is each line a separate division (similar to the A and B divisions like in New York; where I hail from )?
Thanks in advance for any answers,
R32 - Sea Beach Express

As for what the chose you for (i.e. guard, motorperson, or bus driver) I believe it is whatever they need at the time.

As for which line, I beleive each is seperate, not sure about how the seniority works....just been seeing some of the same faces on the Orange Line for about 15 years or so.

Hi all, I just wanna let you know that since this thread has more to do with employment, I will be relocating this one over to Employment (General Discussion).