Originally the New York and Greenwood Lake RR, acquired by the Erie a long time ago.
Newark Branch came off the Greenwood Lake right near the DB draw over the Hackensack Rivere....and also the Orange branch and Caldwell branches came off the greenwood lake line.
Connecting track to the ex-DLW boonton line that crossed at a diamond at Mountain View, was made in 1962, and former DL&W mainline trains to Dover via Patterson, now took the Ex-Erie Greenwood lake line to Mountain View, and then the DLW Boonton to Denville, when it joined the M&E.
Former Erie employees always call the line the "Greenwood Lake", and the ex DLW employees called it the Boonton. LOL.
In the 1990s (???) the ex lackawanna Montclair branch was connected to the ex-erie Greenwood lake line at Montclair, .
All trains (just NJT now) now run DLW M&E (under the wires) to montclaie, ex erie Greenwood lake to Mt View, and Ex DLE boonton to Denville.
The ex-erie Greenwood lake between Croxton yard, West End tower, and Montclair was abandoned. This was at least partly done to save the cost of fixing the swing bridges at Arlington (5 mph speed restriction) and at DB.
The abandoned portion is supposedly going to become at biking trail...