MN's signal system was upgraded in recent years to a cab signal based system. NYCTA's signal system is the same one they've largely been using since the day the system opened. They're old and they're tired and parts availability isn't what it used to be. The MTA has been working on upgrading the signal system throughout the system, but that takes time. The "A" division (i.e. the numbered lines formerly the IRT) are all currently being upgraded to an electronic system, which is how the "countdown clocks" have been made possible. I believe that the #7 line is in line for signal system upgrades, if they're not already in progress. They aren't however anywhere near done, so in the meantime, until the upgrades are complete, you'll have to live with "signal problems" in your daily commutes.
If you want these projects completed sooner, lobby all of your state representatives in Albany to fully fund the MTA's Capital Program, which is where the funding for major upgrade and construction projects comes from.
5th generation from Harmon (Croton-on-Hudson, NY), home of the MTA MNRR Harmon Shops.
B.S. Elec. Eng. Tech., Rochester Institute of Tech.
"I have problems sleeping at night when I can't hear the idling of several GE locomotives reverberating off the hills."