Boarding tracks are supposed to grab and hold carts when unpowered, and then launch them in the direction of the arrow when powered. They do neither.
Holding tracks don't hold or release. Control tracks don't boost, but do change direction upon redstone signal. Booster tracks don't boost. Disembarking tracks don't disembark
I guess default boosters kinda work, they push you but don't stop you like they should unpowered from my quick test. But the main rails not working properly is really killing it. Tried to setup my little station and just nothing worked.