Market-Frankford Line Signalling System

Hello! I'm currently in the process of creating a game based on the Market-Frankford Line.
If anybody could share some information about the signalling systems the MFL uses, I would greatly appreciate it

I don't know what type of cab signals they use, but they do have wayside signals for the interlockings. BTW, will this game of yours just feature the M-4s, or will it also feature the Almond Joys as well?

RDT: Welcome to the SEPTA Forum...You can start by searching the SEPTA Forum Archives for
information on the Market-Frankford Line - there are 20 years of topics and posts available...
Railroad.Net 20th Anniversary: March 11-12, 2004 is when this site began...

I would also suggest Market-Frankford Line videos available on YouTube for starters...
From 69th Street Terminal to Bridge/Pratt (Frankford Transportation Center) is about a 45 minute ride...
There are head-end or Train Operators view videos available specifically...

BC - I would rather describe the 1960 Budd cars as the previous retired M3 car fleet...
Not everyone remembers their nickname from the four fans/air intakes on the roof of each M3 car...
Now that they have been retired and out of service for 25 years...The M3 cars ran from 1960-1999...

Just remember - "You Can't Get to Heaven On the Frankford El"
There is a past SEPTA Forum discussion - and YouTube video available - with this song title...MACTRAXX