Article about various bridge replacements around the USA. ( although canada and Mexico should have been inclued ). The article does not cover the many wooden bridges needing replacing either from actual fires or possibility of one. Another factor is the requirement of replacement bridges to have more lateral clearances over navigation waterways and not be swing bridges ?
UP certainly has had its hands full with several bridge failures this year.
It is amazing that so many present bridges were either built in the late 1800s or early 1900s. Can we guess that the RRs are building
Most bridges were built during the era of railroad expansion. We are not in that era. We are still in the era of railroad contraction. Bridges cost big bucks and railroads don’t desire to spend much these days.
Many of the railroad bridges from the days of expansion were significantly overbuilt - the days of computers designing structures that are “just strong enough” had yet to arrive.
As tired as some railroad bridges look, they’ve still got some life in them.
IMO rairoading will never be the same as it was in the steam era.That was a different time.
I watched and photographed removal of a short wooden trestle being replaced with a pre-stressed concrete bridge over a small river (not even a creek by western standards) near me a few years ago. They had to keep the line open for traffic during the process and acconmplished that goal.
The civil engineer who oversaw the project liked the photos because as he said “They tell a story from start to finish”. The concrete bridge with a ballast deck was designed to last at least 100 years.
On my trip back from Jacksonville to Maryland in August, I drove I295 past Benning Yard. Catenary poles were still standing at that time. I suspect they are now carrying power for commercial use, otherwise I suspect they would have been removed long ago.
(1) The Class 1’s are doing just fine as are the regionals (Class 2’s), especially with their steel bridges. If there is concern, and there is considerably less than in years past (thanks to FRA’s Bridge Management Program), is the shortlines. The ones with the “we run trains” mantra are the scary ones and FRA finally woke most of them up. (and hint: Cooper’s rating system was a steam era creation, but it still works well and creates some unwanted dynamics that will accentuate where there might be a problem)…Wooden bridges are fine, but you have to respect how wood deteriorates and the number of cycles which speeds up the decline of service life. You can run 315K loads instead of 286K (or 263K) in many cases, but you just shortened a bridge’s remaining lifespan (a concept over the heads of so many operating bubbas of the “we run trains” persuasion)… The yellow peril is having issues with non-structural issues outside their control in the cases sited above, usually caused by changes upstream in drainageways or by foreign objects hitting the bridge. (Joe K has the CSX equivilent of the Enid “Can Opener”)
(2) If you must worry, don’t worry about the railroads, worry about the county and local level road bridges and hopelessly overweight trucks on the most deficient of those bridges. (just dealt with a concrete truck that dealt-in one of those in rural CO…and the truck didn’t float.)…We still have 4+ lane federal highways out here running on timber bridges that the motoring public is blissfully unaware of… but the local media in many places is obsessed with rusty railroad steel structures)
You also need to remember this about the locomotives. What did a big steam engine weigh in at well over 400K lbs was normal weight. The Big Boy is well over 1 million lbs fully ready to run. That is a lot of dynamic loading with the thrusting going back and forth with the drivers and rods. A modern GE or EMD is half that.
Now go run those beasts on lightweight track and bridge structure (with limited throw couplers thrown in at no extra charge) and see what that does to your physical plant. The canary in the coal mine will be the backtracks,curves and switches, followed by the least capable bridges as your shortline self-destructs.
When in France a few years ago, I drove to see a Roman Viaduct that has stood (per Wikipedia) since 40 AD. It is very impressive. While it dosn’t carry water anymore, it still stands. Wonder what it’s lifespan is?
Wonder how B&O’s original viaduct and PRR’s masonry bridges are holding up? The British Railroads have some magnificent structures also and they appear built to last.
Thomas Viaduct at Relay, MD is still carrying all the traffic of CSX’s Capital Sub between Baltimore and Washington - Freight and Passenger. Lord only knows how much EHH will allow for continuing maintenance. It was opened in 1835.
Carrollton Viaduct in Baltimore still stands and is still handling yard traffic at Mt. Clare Yard. It was opened in 1829.
PRR’s stone bridges have had some problems. I remember the photo some years back in Trains of a partial collapse of an arch on the Rockville bridge. Many photos of PRR stone bridges show steel bracing.
The first bridges over major rivers in the upper midwest were not in service long. Many of these bridges over the Mississippi and Missouri Rivers were replaced in the last decade of the 19th and first quarter of the 20th century.
Many of these second bridges are still in use, or have been recently replaced. A century, or more service is a tribute to those who built them.
What is the expected service life of new rail bridges spanning long distances?
I can’t help but be reminded of some monumental bridges and the engineers who designed them. Gustav Lindenthal designed three still-used-today railroad bridges that I’ve seen and admired:
There is no question of the enduring quality of Lindenthal’s bridges. For a non-rail bridge, my personal favorite is the Samuel Beckett vehicular swing bridge in Dublin, Ireland, which is designed to resemble the Irish national emblem of a harp:
