print("Finding host")
peripheral.find("modem", rednet.open)
local id = rednet.lookup("main", "TRAIN")
if id then
  print("Found my_host at computer #" .. id)
else
  printError("Cannot find host")
end
while true do
  local event, sender, message, protocol = os.pullEvent("rednet_message")
  if protocol == "TRAIN" then
		if message == "GO" then
			local rear = rs.getAnalogueInput("front")
			if rear > 0 then
				rs.setAnalogueOutput("back",15)
				sleep(1)
				rs.setAnalogueOutput("back",0)
				rednet.send(sender,"OK")
			else
				rednet.send(sender,"NF")
			end
		elseif message == "OFF" then
			print("Server disconnecting. Automode turning on")
			while true do
				print("Working on automatic mode")
				local rear = rs.getAnalogueInput("front")
				if rear > 0 then
					sleep(30)
					rs.setAnalogueOutput("back",15)
					sleep(1)
					rs.setAnalogueOutput("back",0)
				end
		end
	end
  end
end