The Modoc was unsignalled except for the automatic interlocking at the BN crossing at Stronghold, and a stretch of ABS/Absolute Permissive Block (sort of a local CTC) between Wendel and the WP/UP connection at Flanigan. Train-order dispatching was replaced by Direct Traffic Control (authority to occupy "blocks" (not signal blocks) of trackage given to trains via radio; SP did not use TWC. In its latter days, Modoc traffic seemed to be more or less two trains each way a day, mostly Oregon lumber headed east and lumber empties returning.