From an L&HR Employee Timetable, Absolute Permissive Block (APB) Rules were in effect between Maybrook "BK" and Belvidere "G Tower". APB Rules also required Train Orders to be issued for authority to occupy the main track for all extra (freight trains) trains not listed in the timetable.
Generally, only First Class (passenger) and Second or Third Class (regularly scheduled freight trains) were listed in a schedule as having authority (no need for a train order) to operate on the main track without train orders. The "schedule" listed times those trains were to be at specific stations/locations. Extra trains not listed needed train orders to operate.
Although NE-3 "always" went on duty at Warwick at 19:00 Daily, it was still an "extra" train and needed train orders to occupy the main track.
NOTE: The "contemporary" equivalent of APB rules would be NORAC's "Signalled DCS Rules". The Train Dispatcher doesn't actually have control over the signals in APB; he/she issues train orders/Form D's/etc to authorize trains/vehicles on the main track. The signals only provide protection against broken rails/collisions; the signals back up the written train order.
I participated in another topic regarding the interaction of the signal system and train order offices/interlockings. See here:
http://www.railroad.net/forums/viewtopi ... 88&t=17923
Hope this helps.