That bridge is the 3rd one at that location. There was a wooden bridge built in 1855, an iron through truss in 1871, and the present one, built in 1914. The cutoff was open, but they still must have had enough heavy traffic on the old road to need a new bridge.
There is an interesting story behind the 1871 bridge. When DL&W built the present one they sold the 1871 bridge, just south of the 1914 bridge, to an enterprising "man of the cloth," Henry Darlington. He opened it as a toll bridge for autos, and it remained in use until newer bridges were built, demolished in 1954.
The following link has a picture of the 1871 bridge after being converted to highway use. You can see the 1914 bridge in the background on the right.
http://books.google.com/books?id=dDDDUl ... CGkQ6AEwCw
In the early 1970's there would still be occasional hoppers parked on the Jersey side of the present bridge, although the rest of the old road on the NJ side was gone.
Up until the late 80's / early 90's there were also 2 bridges over route 46, one to carry the old road, lining up with the present bridge, and a 2nd road bridge, slightly south, lining up with the 1871 bridge.