Constructed a railcraft elevator program, code below

[if input == "1" then
end
if input == "2" then
rs.setBundledOutput("left", colors.red + colors.white)
sleep(4.0)
rs.setBundledOutput("left", 0)
end]

and so on and so forth up to 16 levels which are spaced 10 bricks apart before ending
[print("You have arrived at your destination.")
sleep(1)
os.reboot()]

I get a calling nil error when the program attempts to reboot (line 82, [os.reboot()] as above), but i can fix that just fine. More importantly, the cart can't seem to climb up above the first level. Forgive me if I haven't given you enough information but I'd rather not include code for each individual level, so I tried to just give you all what you might need to help me out.
I have attempted to diagnose the problem myself and it looks like upon leaving the boarding track, the minecraft can't travel up the elevator tracks because they aren't receiving power. This is not the elevator track's fault as most of you probably know, so it is either the bundled/insulated cabling or the computer's. I can't discern whether or not the problem is the cables carrying the signal or the computer producing it. I feel less inclined to believe the coding is the issue as lower floors work while higher ones do not. I imagine the problem may have a really simple solution, but I can't for the life of me figure it out.