Here's your link: http://historical.mytopo.com/getImage.a ... g&state=PA
. After coming off the Catawissa main at Hazelton Junction, it looped up and over the Lofty tunnel as you noted, and then went 3 places. The first I think historically was Silver Brook Mine, the white patch on the map just below Haddock with Route 309 going through. 2nd, there was a CNJ (originially L&S)Treskow (or Audenried?)branch that came off of it, which is on the map, that then went east and then looped north and back west, to go to mines just north and west of McAdoo. The CNJ used the Reading to reach it. 3rd, there was a Reading subsidiary Tamaqua Hazleton and Northern that branched off which more or less paralleled the LV (on the south east side of it) up to just south of Hazelton (to "Roan") to try to collect coal from the Hazelton area. It never succeeded since right after it was built the LV bought a lot of the mines in the area from the Eckley family, so the THN came up empty handed. It must have been gone by the 1955 date of the linked map. My guess is that it was because of the THN that Hazleton Junction on the Catawissa main got its name. In the early days these branches didn't loop over the tunnel -- they tied into the main directly at Lofty , where there was a wye. Not sure why the overpass you noted was built.
Some more discusion is here:
http://www.railroad.net/forums/viewtopi ... ty#p741382
http://www.railroad.net/forums/viewtopi ... hn#p452280
http://www.railroad.net/forums/viewtopi ... &hilit=thn