UP/BNSF Crossing Incident Collapses Highway Bridge

[C855B]

http://www.cbsnews.com/8301-201_162-57586201/massive-missouri-train-collision-takes-down-highway-overpass/

I've railfanned this crossing. As you can see, the crossing is directly under the bridge: http://goo.gl/maps/YotSZ

[GaryHinshaw]

Wow, what an unusual track/road configuration.  Along with the Tehachapi collision, it's been a bad week for vehicle trains.

Turns out to have been a bad week for bridge collapses too.  The I-5 bridge over the Skagit River collapsed earlier this week, cutting off the main artery between Seattle and Vancouver.

-gfh

[Specter3]

We have one of those here in Charlotte as well. CSX crosses NS under a highway overpass. I am actually modelling that crossing on an Ntrak module. And I could easily see a collapse happening if NS went off with any velocity. CSX always stops there so they are never moving with any speed.

[C855B]

LOTS more pix here: http://www.kmov.com/news/editors-pick/Photos-Train-collision-overpass-collapse-bridge-208935291.html?gallery=y&img=1&c=y#/news/editors-pick/Photos-Train-collision-overpass-collapse-bridge-208935291.html?gallery=y&img=0&c=y&c=y

[nkalanaga]

Mike:  I looked at the site on Google Maps.  It seems to have been well signaled.  Do you have any info on who has the right of way, who controls the crossing, etc?

[C855B]

No, I don't know for sure who controls the crossing, but odds are that it's the UP given they have nearly 3X more trains over it.

[lock4244]

At least no one was killed and the injuries weren't life threatening. One assumes the UP train was at fault given the BNSF train was already at the crossing and the UP ran into it. One assumes...

[Denver Road Doug]

At least no one was killed and the injuries weren't life threatening. One assumes the UP train was at fault given the BNSF train was already at the crossing and the UP ran into it. One assumes...

Why would the fact the one train crossed first make you assume the other was in the wrong?  Crossings are controlled by signals or other very specific rules.  It's not "who gets there first". 

[Dave V]

Why would the fact the one train crossed first make you assume the other was in the wrong?  Crossings are controlled by signals or other very specific rules.  It's not "who gets there first". 

Fair enough, but even if the BNSF train ran a stop signal to occupy the crossing, should not signals on the UP main also have indicated stop due to the crossing being occupied?  Perhaps they did but changed too late?

[C855B]

... It's not "who gets there first". 

Actually...

An automated crossing is "first-come, first-serve". This particular crossing is of the type that might have been converted, but I don't know that. I do know the signals have been replaced since my last visit there. With automatic crossings, obviously there is rather overbearing occupancy control logic with lots of fail-safes, so somebody certainly can't get a clear signal to occupy the diamond with any chance of throwing a red in a conflicting train's face after it's too late to stop.

We'll just have to wait for the NTSB report. Somebody overran their stop-and-stay, or signals failed (unlikely), and that's 'bout it.

[jagged ben]

Fair enough, but even if the BNSF train ran a stop signal to occupy the crossing, should not signals on the UP main also have indicated stop due to the crossing being occupied?  Perhaps they did but changed too late?

I read that the UP train hit the BNSF train only 12 cars back or so.     Depending on the speed the BNSF train was traveling, that would mean the UP train would probably have had only a matter of seconds to stop.  Maybe 30 seconds at the most.    Which is not enough time to stop a freight train at speed.

[Denver Road Doug]

Nevermind, you guys are right...we should just assume the UP train was wrong based on what we know.    Whoever gets to the crossing first, no matter how far away the other train is, is CLEARLY the winner no matter what.   

And those damn trains should steer clear of automobiles at grade crossings, too.   

[nkalanaga]

If it was a traditional interlocked crossing, both routes should have Stop indications, which would only clear if there are no conflicting movements, when the first train arrives.  How the modern automated interlockings work I have no idea.  If either route shows "Clear" until a conflicting movement arrives timing could be the problem.

In this case, it doesn't look like either train won...

[Hyperion]

I cannot post details of the accident pending a full investigation, but I've seen the dispatching replays.  And they match crew interviews.  There's a pretty clear line of fault here.  It's definitely not a situation of "first come, first serve", but let's just say that early indications indicate some of the earlier presumptions of fault appear accurate; even if the reasoning isn't correct.

[draskouasshat]

Nevermind, you guys are right...we should just assume the UP train was wrong based on what we know.    Whoever gets to the crossing first, no matter how far away the other train is, is CLEARLY the winner no matter what.   

And those damn trains should steer clear of automobiles at grade crossings, too.   

Actually, theres 2 of us here that actually do or have worked on a signal system so theres usually a level of accuracy from either C855 or I. If this was an automatic interlocker, it would depend on who owns the actual crossing to say who would have to stop. Like the Enid auto interlocker, it used to be non dispatcher controlled and BOTH RR's had to stop, press a button, let time run, and then get a clear. Now, if C855 says it has been updated/PTC installed, if the BNSF owns it, our DS could very well line through it and BNSF would NOT stop until UP came up, pressed the button, waited for time to run, and then got a clear. Now, if it was a manual interlocker, the DS would have FULL control and line either RR through.

The biggest thing, we have a LOT or relay logic, failsafes, built in and tested programming and on and on. Ill just put it this way, when it comes to collisions, its usually user error, not signal error. Dont get me wrong, signal systems screw up, lightning and overhead lines can do crazy things, and theres all sorts of things that can screw things up, but usually our testing keeps a signal system in check.