trainPlaceTrackV2

turtle.select(1)
bigSleep = false
count = 0
function check_inventory()
    local all_empty = false
    local data = turtle.getItemDetail(turtle.getSelectedSlot())

    while (turtle.getItemCount(turtle.getSelectedSlot())) <= 0 or (data.name == "minecraft:magma_block") do
        print('Moving slot')
        if turtle.getSelectedSlot() >= 16 then
            turtle.select(1)
            if all_empty then
                print('All inventory slots empty, shutting down')
                exit()
            end
            all_empty = true
        end
        turtle.select(turtle.getSelectedSlot()+1)
        data = turtle.getItemDetail(turtle.getSelectedSlot())
    end
end

while true do
	while turtle.detect() do
        sleep(0.5)
		bigSleep = true
	end
	if turtle.detectDown() then
        turtle.back()
	end
	if bigSleep then
		sleep(7.0)
		bigSleep = false
	end

	if count > 15 then
		turtle.select(16)
	else
		turtle.select(1)
	end

	check_inventory()

	if count > 18 then
	    count = 0

	end
	count = count + 1

	turtle.placeDown()
	turtle.forward()
end