then you guys don't know rails too well. by turning off the power on a rail, the collision detector will stop looking for collision as it won't move.Its the same reason docked power generators create lag. The system is constantly running collision checks.
that's why it took me 10 hours to make a gigantic 35 degree angled door with 8 pieces on 1 line. scrapping the glitches from starmade and the colouring it took me about 3 hours. I made it that if all pieces were in place, the rails would shut off. it was made on request of blackhawk because he noticed lag coming from the door made by collision detectors, after making the system he didn't have the lag anymore.