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Walked out of my house this morning to see plumes of black smoke in the distance and I came to find out that a Union Pacific train derailed on the over 100 year old bridge across the Salt River, which is now Tempe Town Lake.  A portion of the bridge on the south approach collapsed.  According to local radio news the conductor is currently working with over 90 fire fighters to help determine the contents of each of the cars. 

I'll be curious to see what the official reports state on the cause.  UP maintains this track well as it is their only access to the Phoenix Metro area at this time. 

This one hits home as I have always enjoyed watching trains cross the bridge and photographed UP 844 on the bridge in 2011. 

The local online news posted this story with photos.  UP Derailment

Original Post

Agreed.  The portion of the bridge that collapsed was all on the land side of the south approach.  There is a strip of Tempe Beach Park that extends under the bridge north of Rio Salado Parkway and a vacant lot southwest of the road and the bridge.  That is the portion that collapsed.  

The good news is that there are no reported injuries and nothing ended up in the water.   

After this is all cleared up, a big question I have is that how will UP access the Phoenix market during bridge repairs?  The western sub was put out of service in 1996 so there is no other all UP route to get into Phoenix.  There is a a very rough single track connection that runs west and north past downtown to the BNSF yard, but the routes from there all go west to Wickenburg and then either north on BNSF to the mainline or west to the BNSF mainline on the Arizona & California which is owned by Genesee & Wyoming.   

@GG1 4877 posted:

After this is all cleared up, a big question I have is that how will UP access the Phoenix market during bridge repairs?e or west to the BNSF mainline on the Arizona & California which is owned by Genesee & Wyoming.   

Most likely by having BNSF pick up or deliver cars in interchange with UP (ex-SP) at Phoenix.  UP would then switch its customers.

This will probably add two or more days to the transit times of Phoenix UP cars to and from the east, but it will continue to provide service to customers.  To and from the west, maybe a day or two extra simply because there is one train a day between Cadiz and Phoenix.  BNSF runs more trains east.


Last edited by Number 90


Thanks for your professional insight.  We are still in a construction boom and that effects a lot of workers here in this part of Arizona.  BNSF doesn't seem to carry the same level of commodities for construction that UP does to Phoenix, but that is just based on observations of what kinds of cars I've seen in both yards and the relative size of the yards.  The Cadiz interchange does make sense.  It is a pretty direct route but as you state there is not a lot of traffic on it.  UP was running about 15 trains a day into Phoenix prior to their latest slowdown.    

Last time I saw the connection track between the yards it was rough.  Probably limited to 10mph at the most.  It's one of several curves that I refer to as the "0-27" curves that snake their way through the Phoenix metro area.


@GG1 4877 posted:

After this is all cleared up, a big question I have is that how will UP access the Phoenix market during bridge repairs?  The western sub was put out of service in 1996 so there is no other all UP route to get into Phoenix. 

Just build a connection to the Valley Metro before the park.  That bridge is still standing

Yes, I am joking.

It will be interesting to see how this all plays out.

Sometimes a back up line makes sense.  Could one imagine Houston being served with just one line....even if one takes out the Port abd refinery traffic.....!

Interestingly enough, Phoenix was never on any mainline railroad of any size.  It is due to the fact that Phoenix didn't become a major city until after WWII.  The former SP Sunset Route runs south of Phoenix by about 25 miles.  Instead there was a branch line built starting partway between Tucson and Phoenix that was built to Phoenix that continues to interchange with some mining railroads.  From Phoenix the branch continued SW to a small town outside of Yuma on the CA border.  

In 1996 either SP or UP (I don't remember at the moment), took most of that line out of service.  The Amtrak accident at Hyder was the official reasoning at the time, but I suspect SP was looking to drop the line for a while.  It currently is used as a storage track for obsolete auto racks, and well cars for the most part on about 60 miles of track and has trees growing through the right of way.  Before the traffic turndown there was talk of putting that track back in service.  

BNSF is in the same position.  ATSF built south from their transcon about 60 miles west of Flagstaff on what is locally called the "Peavine" due to the terrain and also built west to Cadiz.  Genessee and Wyoming currently owns the Arizona and California for the portion of track that goes to Cadiz.  

Terrible news. We have been to Tempe many times over the years, as one of our daughters and her husband attended ASU. We stayed at the Courtyard, which is only a couple of blocks from the bridge, and I took my morning runs in that area. Sad that at least one of the spans of the bridge has been lost and I hope that the lake has not been polluted. The only good news is that it appears no lives were lost. I would imagine that it will take quite a bit of time to do the necessary repairs and reopen the line. 


@Rich Melvin posted:

Hmmm...I wonder if the Division Roadmaster and/or Bridge Inspector might be looking for a new job soon.

This should not have happened.

Rich it is interesting because apparently the bridge just got inspected on July 9th.  Agreed this never should have happened.  While it was built in 1912, it is one of two bridges to survive the massive flooding that took out every other bridge (about 7 or so) on this river system through the Phoenix area except for two in 1989.  The other bridge was built in 1910 for horse carts.  Speeds are not very high as there is fairly sharp curve north of the bridge.

I don't like to speculate on the cause until at least some investigation has been done.

A few photos from better times on this bridge from 2011:

Not the best photo, but this is one of the sections that collapsed.


About mid-span


The dynamic brake on the rear



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Last edited by GG1 4877

Since I live within sight of the BNSF (Santa Fe) Peavine, here we are wondering if we will see UP diesels!!  Or more than the usual 10 - 12 trains a day (total, both directions).  This would be the logical route for traffic coming from or to the east into Phoenix.  Even if the line to Welton were to reopen, that would be quite a backhaul, going west almost to Yuma, then 150 miles back to Phoenix. But at least that would keep the traffic on UP tracks as the other two options mean routing it via BNSF.

@Rick Rubino posted:

as most of the train passed over the bridge maybe it was a derailment that took out the bridge rather than the other way around.

Much more logical. I have also read speculation that that empty center-beam car just might have had an overheated roller bearing, which burnt off the axle, setting fire to the bridge beam & ties as it moved along, eventually completely derailing and tearing down that section of the bridge over the land. All speculation of course, but sure sounds logical.

Jack, That is good information to know. It makes total sense for the load restriction on the bridge. They did not turn the locomotive as I have photos from all three days the 844 is in town and when it left town it was the trailing unit. Looking back at my photos when it came into town the auxiliary water tender was just forward of the SD70.

Peter, If you see some UP on the Peavine hope you get some photos!

Rick, While I really don't want to speculate, a structural failure of the bridge seems very likely whatever the cause. It could have been to a poor inspection and a weakened load capacity or as you suggest, one of the cars left the rails and impacted the truss. There was a short discussion on teams for my office this morning and a co-worker who lives near there said she heard a loud boom just as it happened. Obviously lots of things could have caused that.

The latest news was that the tank cars did not leak and the photos look like mostly covered hoppers ended up burning. I'll probably head down there on my bike after everything has settled down over the weekend. There is a park on the north side that has some short buttes with excellent views and is well off the right of way.

Last edited by GG1 4877

They hardly ever build new steel truss bridge spans any more, as the overhead and side clearances are annoying, plus there is always the possibility that a derailment can collapse the bridge.  Whatever is done will need to be okayed by the Army Corps of Engineers.  Any steel trusses which are to be removed are still coated with lead-based paint,* and that will cause extra delay.

The most likely first-choice replacement would be pre-stressed concrete deck spans, but the spacing of the piers could be a problem.  There is a practical length limit for concrete, and it may or may not exceed the length of the truss spans.  Maybe there is someone on the Forum who could shed more light on this factor.

I wonder how far it is to the closest hotbox detector?

*  Maybe not the current top coat, but probably a century worth, underneath the current coat.

Last edited by Number 90

Thank God it appears that there have been no injuries or deaths reported in this tragic accident. 

While it's too early to speculate on the cause of this derailment, it must be remembered that most railroads today have far fewer car inspectors on duty at major terminals than years before.  While employed as a switchman/brakeman in the greater Dallas/Ft. Worth area on the Cotton Belt in 1967-68 and Santa Fe from 1968 until my move to Germany in late 1977, car inspectors checked every car of every train due to depart their respective terminal.  This even included checking the metal bands that secured lumber loads on flat cars.  Over the years I switched out a good number of defective freight cars.  Once bad ordered, cars were spotted on the rip track to be repaired before they could continue on to their final destination for unloading. 

Modern Century 21 railroading has eliminated most car inspector jobs and the ones remaining are under pressure to see that trains leave the terminal after they've been made up ASAP.

I was also employed on the Deutsche Bundesbahn in Germany as a switchman/brakeman before I transferred hiring on as a passenger service represenative at the main train station in Nuremberg.  After the railway was "privitized" (it's still owned by the German government, albeit operating as the Deutsche Bahn) the downsizing of the labor work force began in earnest.  Since then, accidents have increased as a result of goods wagons (freight cars) not having been properly inspected, if at all...?  For example, it's not uncommon to have to stop a train due to a leaking tank car, or shifted load, having them switched out to repair a malfunctioned valve or resecure a load of lumber, respectively.

I retired in 2010 at age 64 and have no regrets.  Do I miss railroading?  Does a bear sleep in the forest?  Where on earth would I like to work if I could again?  Germany?  Texas?  Nope.  It would be on the Strasburg Rail Road in the Pennsylvania Dutch country no less!

All aboard!

Joseph Toth Jr.



Update:  This morning a little ofter 8 am, demolition crews did a controlled blast to remove the damaged portion just north of the span that collapsed.  Trying to find details, but it sounds like the UP will replace the two demolished sections and leave the rest of the bridge intact.  It is good new that most of the iconic structure will remain.  It will be interesting to see what the replace the spans with, but as Tom stated above, I suspect it will most likely be pre or post tensioned concrete.  

Demolition of damaged spans


Why does the Army Corp of Engineers be the ones to approve the bridge?  The waterway is special to the DOD?

Probably because if fits in their mission statement.  From the Army CoE website:

Deliver vital public and military engineering services; partnering in peace and war to strengthen our Nation’s security, energize the economy and reduce risks from disasters.

Seems to tick all the boxes.




Even though there is a lake there now, it is an artificial lake with operable dams on the west side and only dates back to 1998 or so.  Prior to the damming of the Salt and Verde Rivers in the 30's as part of WPA project to provide reservoirs and hydro electric power in the mountains NE of town for the Phoenix area farms in the 1930's, the Salt River ran all year round. The Army Corps regulates it as a navigable river and about every 5 years or so due to heavy summer rains, there are controlled releases into what is mostly a dry river bed outside of Tempe Town lake, and several miles of reclaimed habitat in south Phoenix.  Navigation on this river is questionable at best like most rivers in AZ that have been dammed to provide reservoirs.

When we measure water in our washes, streams and rivers we do it in cfs (cubic feet per second)   The joys of flash floods and the desert.

The Army Corp does not manage the lake.  It is fully managed by the city of Tempe and they used ground water to originally fill it.  The city is responsible for all lake associated costs.  The Army Corp has jurisdiction though and that is why when there are large releases from the reservoirs to the north, the dam walls are dropped and water flows freely through there.  Also, any development within the channelized portions of the wall are under the jurisdiction of the Army Corp.  I don't pretend to know all the details of the arrangement.

Last edited by Rich Melvin

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