For those who don't know, 'back in the day' the PB&NE was Bethlehem Steel Co.'s wholly-owned "common carrier" switching line at and in its Bethlehem, PA plant. It connected directly with 2 'outside' railroads, the Lehigh Valley RR to the north and the Reading RR to the south and west, so as to enable the steel co. to get pretty good rail access and some competition on rates, etc. Although "The Steel" has been gone now for about 10 years, the railroad and a small fleet of switchers still survives and thrives, under the name of "BethIntermodal" of Lehigh Valley Rail Management ("LVRM"), serving a small (but growing) industrial park on portions of the site of the old steel mills, and a pretty busy multi-faceted intermodal and transload terminal - NS Triple Crown's RoadRailers, double-stacks, piggyback, etc. - see: http://www.bethintermodal.com/ and http://www.bethintermodal.com/locations/bethlehemfac.shtml
A book on the PB&NE and other internal steel plant railroad operations - including both narrow and wide-gauge ! - has been published: Bethlehem Steel Railroading, by Nevin S. Yeakel*, Publisher: The Railroad Press (August 19, 2008), 56 pages, ISBN-10: 1931477272, ISBN-13: 978-1931477277, about $25, per: http://www.amazon.com/Bethlehem-Steel-Railroading-Nevin-Yeakel/dp/1931477272
(*Several others also by Mr. Yeakel - perhaps earlier versions or drafts - appear to be at the Bethlehem Public Library only, but I haven't seen them yet.)
Nevertheless, there doesn't seem to be any photos of ithe PB&NE's 2 largest bridges available on-line, although there are many of tis locomotives - see: http://www.railpictures.net/showphotos.php for "PBNE" and/ or "LVRM", etc., and about the middle of this webpage: http://www.thebluecomet.com/crlvline3.html
So to fill that evident void in cyberspace, I herewith submit several of my recent efforts for general edification and amusement. I disclaim any greatness in these photos - they were done quickly over a couple of lunch hours with a mere pocket digital camera while keeping an eye out for the busy road traffic, and I had no ability to adjust the exposure for the darkness of the subject and underneath and the great contrast with the bright sky above. Maybe someday I'll get back with a better camera and time and lighting conditions good enough to take advantage of it . . .
Old PB&NE herald on the 'new' (circa 1960's I guess, from its appearance and construction) high bridge over PA Rt. 412 about 1 mile north of I-78 at Hellertown, at these Lat./ Long. coords. per the ACME Mapper 2.0 application: N 40.60863 W 75.33953

Long view of same, looking northward, with a train being shuffled on the bridge - the 'newish' Sands Bethlehem Casino is about 1 mile ahead on the left, built on some of the former BSCo plant:

The bridge(s) over Shimersville Road and the Saucon Creek a little to the east, at: N 40.61160 W 75.33657 One of my colleagues jokes that this bridge has about a year's worth of production of steel from the mill in it. Actually, it's a pair of parallel ballasted deck truss bridges, which are not identical, and that makes them appear more massive than they really are. I'm not sure when they were built - a fair guess is early in the 20th century for one of these bridges, when the slag from the older plant was dumped out this way, as well as serving the coke ovens farther south; the other bridge probably dates to the early 1940's, when the plant expanded onto another 1,500 acres (2-1/2 square miles) off to the east as part of the build-up for the World War II industrial effort. That expansion is now just about all gone/ demolished, and has been partially replaced by a new 'brownfields re-use' industrial park - LVIP VII, see: http://www.lvip.org/AvailableLand.htm - part of which is the LVRM intermodal terminal.
This view is looking eastward - the near span now has only a gravel roadway on it:
This view is looking westward - the near span is the one with 2 tracks on it - note the floodlights and the metal guard to keep debris off the trains from falling onto the roadway:

Looking southward - the span carrying the 2 tracks is one the left, and is presumably the newer one - note the solid and 'cleaner' "I-beam" type members as compared to the 'lacy' built-up cross-braced members on the span to the right which carries just the roadway, although they are all still riveted together. The laid-up stone abutment below looks kind of crumbly to me, but it's the concrete behind and above it that really carries the weight of these bridges. Note that the bottom chords of the one on the left bear on the low concrete foundation there - but the lower chords of the one on the right are just hanging in mid-air ! What's up with that ?
The answer can be seen in this photo of the other end of that span, looking northwesterly. The bearing point is at the upper right, on top of the high concrete wall, and the rightmost member slopes down at about a 45-degree angle, so that the overall shape of this bridge resemble a series of "WWWW" strung together - there are no vertical or horizontal members at the very ends. In contrast - although it's hard to see in this photo's view - the other truss has a rectangular shape, with a vertical and a horizontal member at each end, kind of like this: "|WWWW|
Now, why was that done ? Well, I surmise it's the same reason as the left truss has all those lacy webbed built-up members - back in that day, steel was expensive and labor was cheap, so it was worthwhile to take the time to fabricate and rivet together all those little pieces. Likewise, for the slight added cost of a taller abutment wall for the end bearings, that bridge could save several dozen tons of steel by eliminating those end vertical and horizontal members. In contrast, when the other truss was built, steel material was easier to come by - "they made it here", remember ? - so it was faster and more economical to just use single solid pieces that needed minimal fabrication. And actually erecting that other truss would be a lot easier without needing as much temporary 'falsework' to support it over the roadway and creek, and less effort put into the strengthening of the higher bearing wall, etc.
Maybe some more photos and a few more comments on other details when I have more time, and if there's more interest in this.
- Paul North.
"This Fascinating Railroad Business"
(title of 1943 book by Robert Selph Henry of the AAR)