According to the Erie RR operating timetable, the Orange Branch began at Forest Hill on the Erie’s Greenwood Lake Branch (on the portion where passenger service ceased once NJT completed the Montclair connection to the Newark Branch). To elaborate a bit on the Newark Branch, AFAIK there is still freight service on the western (geographically northern) section. Its drawbridge across the Passaic is just upstream from the M&E bridge and I-280 in Newark, but has been in the open position for decades, so this section is not in service. All the Erie lines, including the original “main line” through the city of Passaic, the “Bergen County RR”, and the branches such as the Northern Branch, New Jersey and New York RR (Pascack), Orange, Caldwell, Newark, and Greenwood Lake lines, all ran to the Erie’s terminal in Jersey City—gone since about 1958 when the Erie’s trains moved to the Lackawanna’s Hoboken terminal, anticipating the merger of the two railroads into Erie-Lackawanna. (The NY Susquehanna & Western also used the Erie’s terminal, but its trains never moved as there was no direct track connection; the Northern Branch, to Nyack, also suffered from the lack of a direct connection and required a backup move to get to Hoboken.) The Jersey City terminal is at the location of the current PATH Pavonia-Newport station, originally called “Erie”, and unless something’s happened the letter E still stands on the original columns on the platforms.
The former Erie and Lackawanna lines have been much realigned over the years. The Lackawanna’s Boonton Line, IIRC conceived as a freight bypass of the congested commuter main line Dover-Hoboken, but also used by some passenger trains, was abandoned through Paterson and replaced by the current Interstate 80. South (railroad east) of Paterson through Hoboken the line very much still exists, and is called NJT’s “Main Line”, an echo of the Erie’s original Main Line through Passaic—which was abandoned and its trains rerouted onto the former Lackawanna Booonton Line to eliminate the troublesome grade crossings through the city of Passaic. Even though the line today may seem to be for ex-Erie trains (to places like Suffern and beyond), stations such as Delawanna should let you know of the Lackawanna heritage. To connect the “real” Erie Main Line in the city of Paterson to the “new” ex-Boonton line, trains operate over a short stretch of what was the northern (RR western) end of the Erie Newark Branch. All this happened around 1960, I believe.
The Greenwood Lake line of the Erie started off the Erie’s main line in the Jersey Meadows. Its abandoned drawbridge over the Hackensack is immediately upstream from Portal Bridge on the NEC; the line is scheduled to become a rail-trail (if anyone can figure out how to get the users across the Hackensack!); the line then went under the NEC, clearly visible from any train today. It then crossed the Passaic and went through North Newark, then coming close to the Lackawanna’s stub-ended, electrified Montclair branch at that line’s terminal in Montclair. It then when north, eventually crossing the Lackawanna’s Boonton line at grade in the area of Mountain View. It continued all the way to, you guessed it, Greenwood Lake.
When the Lackawanna’s Boonton Line had to be abandoned through Paterson, its trains were rerouted on a more circuitous route, using the Erie’s Greenwood Lake line between Mountain View and Hoboken. Still later, NJ Transit finally accomplished its long-time goal of connecting the Lackawanna’s Montclair Branch to the Erie’s Greenwood Lake line at Bay Street, Montclair, which involved abandoning the original terminal, building a new station and the connection, and extending the overhead wires to Montclair State on the Greenwood Lake line; at this time service on the Greenwood Lake ended east of Montclair, although there may be some local freight service (as there is on the former Boonton Line for a few miles east of Mountain View). NJT calls this combination of Lackawanna Montclair Line, Erie Greenwood Lake line, and Lackawanna Boonton line the “Montclair-Boonton Line,” which is where we are today.
One final detail: for years after the move of Erie trains to Hoboken, the “Main Line” and “Bergen Line” (together with the Pascack Line) trains joined at a point in the Meadows; this was the site of a head-on collision of an in-bound Bergen Line push-pull, cab car leading, with an outbound Main Line train, diesel-hauled. The in-bound engineer had successfully concealed a color-blindness problem and he ran a stop signal, colliding nearly head-on with the outbound train where their paths crossed in the junction, killing both engineers and one passenger, seated just behind the in-bound train’s cab. This junction was abandoned when it became necessary to reroute the Bergen/Pascack trains over to the “Main Line” so that all could stop at the new Secaucus Junction station. As a final reminder, although the lower level at Secaucus serves trains from the old Erie lines, it is actually located on the right-of-way of the original Lackawanna Boonton Line. Amtrak’s interlockings on each side of Secaucus’ upper level on the NEC memorialize the history: they are ERIE (on the east of the station) and LACK (on the west).
Forest Hill was a passenger stop on the Erie, probably not on NJT to the end. The next station to the east is North Newark, 0.6 mi, and to the west, Belwood Park, 0.9 mi.
Further trivia: The Greenwood Lake line of the Erie passed under the Lackawanna Boonton Line (which is now NJT’s Main-Bergen-Pascack lines) between West End and Secaucus, near the site of the recently removed coal power plant. After the Erie trains moved to Hoboken, they used a ramp up to the Lackawanna—all this should be easily visible from trains between Hoboken and Secaucus. The Greenwood Lake then runs under the ex-PRR NEC, crosses the Hackensack and shortly, at a place in Kearny that Erie called DB Jct., the Newark Branch diverged to the left through Harrison, crossed the Passaic (drawbridge stands open today), then ran north along the river, crossing under the Greenwood Lake at North Newark, eventually crossing the Boonton Line at Newark Junction near Clifton (this is where today’s NJT Main Line trains leave the Boonton Line and join the former Newark Branch) and finally, at South Paterson, the Newark Branch ended as it joined the original, now abandoned, Erie Main Line, thence on to Paterson (and eventually Chicago).