Thanks for your reply. I tried all of that and still could not get it. But, what I did notice is it doesn't work because the rotation of the spline was not 0, 90, 180, or 270. From what I can see, the spline has to be pointed exactly in one of the cardinal directions. So, I set the spline to point 180 degrees, direct south (the tunnel needed to be pointed at heading 150 degrees S/SE), and it worked perfectly.
Thanks for the help. Really appreciate it.