16 February, Nashua NH — CTC Signals north of Nashua NH to Manchester on Pan-Am Railway’s Northern Main Line were retired the week of February 16th, making this line “dark territory” as far north as Concord. Operations will now be governed by “form D” track warrants. Going forward, a dispatcher will convey authority to occupy track within specific limits. In fact, trains were already using form D track warrants due to the unreliability of the signals. South of Nashua, signals remain in service.
The Federal Railroad Administration must grant prior approval for signals to be deactivated. FRA generally doesn’t favor safety downgrades. This authority often maintains of signal system continuation long they are justified by current traffic levels. A train typically operates north of Nashua, serving Manchester and Concord. Recently the line has carried occasional Bow coal train, but that traffic will soon end for good. A single train is at little risk of collision, but signals also serve to inform crews and dispatch of a broken rail, which would break the electrical circuit controlling the signal block.
Until 1976, The Northern Main linked White River Junction VT and Boston. Passenger trains ran until 1967 with a brief revival in 1980. Three through-freight trains ran daily each way until the 1960’s. By the early 1970s, traffic declined to one Concord — East Deerfield through-train, and two or three unit coal trains weekly. By 1990, only local freights were running.
Unsignaled lines are limited to 49 mph (for freight) and 59 mph (for passenger trains), but current track conditions limit movements at 10 mph. In the fifties this line saw 70 mph passenger trains and 45 mph freight.