Thought up a good setup for making a monitor with LED indicators, 2 possible ways to do it, user input (rider presses buttons along the track as they move) and automatic (pressure pads linked to booster tracks flipping on when the booster is pushed after use). I'll make a good old redstonesim gif when I wake up.
shinryuukai
Shinry,
I have set up a test track in my basement, and have attempted to hit a button or lever on multiple trips around the loop, and if there is NO lag, its still a hit/miss situation. The system should be automatic, no user input needed as they ride. I've installed two bi-directional boosters on the track complete with pressure pads, and it seems to be the better solution. I've also set up a third pressure pad along a curved section of track to take advantage of a speeding minecart's ability to affect blocks set a certain diagonal orientation. This only works if the cart is at speed though, so the booster/pressure pad might be the only foolproof option.
I've started wiring up the redstone to make a 3 point indicator system. It gets a bit tricky though, since the reset leg can also reset the latch that is being flipped. We can use a repeater though, since it acts like a diode. I've sketched up a quick diagram in Paint:
come to the basement when you get online again and help finish wiring it up and test it.
[Edit:needed to fix a feedback flaw, updated image posted above]