When was the LNE line thru East Allentown abaonded? The track is still in, except for a short portion that was paved over to make the NE American Pkwy. There seem to be a lot of potential customers that the track passes right through (factories, industrial parkes, etc). Lots of bridges still in too with track on it.
If you are talking about the brach which crosses 378 off of the Cement Secondary, then I can't give an exact date, but about 4 years ago, perhaps longer now, NS began adding a $500 surcharge for switching the branch which by then only served a lumber yard at the present end of track. NS' extortion worked and the lumber company began trucking thier lumber in from a local transload in an old Bethlehem Steel building.
I drove into the industrial park area to see what was left and found overgrown tracks, some tracks nearly buried in the dirt of various parking lots and several short branches (running north-south). As I recall, the only business along the line that would seem to be rail servicable was the lumber yard.
According to several redevelopment meetings I attended while a resident of Bethlehem, the railroad is being considered for possible conversion to a walking trail.