that is, one track assigned to southbound trains and one assigned to northbound trains. With the advent of Centralized Traffic Control a/k/a "CTC", the River line was reduced to single-track main with passing sidings at strategic locations. Several recent proposals (ca. 2008) put forth plans to either install supersidings (multi-segment extended length sidings), permitting trains to pass one another at speed without stopping, or reverting to complete double-tracking from North Bergen to Selkirk. As of 2008, the original signalled siding (ssdg) between CP-QR 76 (Highland) and CP-QR 78 (West Park) which was 12,500 feet in length, was extended to 24,000 feet with the extension of the original siding to another siding from CP-QR 78 (West Park) to CP-QR 80 (Esopus), with crossovers at CP-QR 78. This extension, known as "West Park Siding", makes the entire length from CP-QR 76 to CP-QR 80 a supersiding. As learned from Ulster County Integrated Advance Train Detection and Arrival Prediction Implementation Plan, page 9 of this document shows one new siding and one supersiding are now proposed to further alleviate rail traffic congestion: a new siding from QR 93 (Lake Katrine/Glenerie) to QR 96 (Mount Marion), and: a new supersiding, which would extend the current existing siding from CP-QR 103 (West Camp) to CP-QR 106 (Alsen), with the extension reaching to CP-QR 110 (Catskill). 2015 Update: Supersidings have now been completed between CP QR 125 in Ravena and CP QR 118 Coxsackie; CP QR 45.5 in Highland Falls and CP QR 43 in Fort Montgomery; and CP QR 38 in Stony Point and CP QR 33 in Haverstraw. Should CSX decide to double-track the entire line, this could be accomplished with minimal difficulty, as the River Subdivision was originally double-track operation (when constructed by the New York, West Shore & Buffalo / New York Central Railroad). As the width of the right of way is already graded for double track, with bridges and trestles already in place that had been constructed as double track, only the re-installation of the second main tracks, turnouts and signals need to be installed. One area of engineering slightly hinders this double tracking, yet it is not insurmountable as it has been done on other railroads and routes. Upon the installation of CTC, one of the two main line tracks was removed, and the remaining main line track was realigned down the center of the some of the tunnels