Author Topic: Tehachapi Derailment  (Read 1262 times)

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trainforfun

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Re: Tehachapi Derailment
« Reply #15 on: January 28, 2023, 03:13:19 PM »
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I thought he said there was a broken rail...?

Exactly what he said !
Thanks ,
Louis



Hawghead

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Re: Tehachapi Derailment
« Reply #16 on: January 30, 2023, 09:27:42 AM »
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Or, apply hand brakes to hold the train until the air was pumped up.  But with no brakemen today, that wouldn't be too practical.

True, but at some point you have to release the handbrakes, so you'd still be in a position where you were stopped on the grade with the train brakes applied.


From reading everything you pro's put put there - its obvious there are a lot of physics/dynamics involved (and a lot of gut instinct from what you guys have posted) in handling a heavy train under normal conditions.  Since most of those forces are known, do the railroad traffic management computers / managers take into account those factors when they (automated?) build the train manifest for weight, grade, pulling power of the engines, etc?

The airlines have a lot of support systems that can calculate flight parameters (fuel,wind, weight, time to destination, etc) as an example. 

Some of you have mentioned the management software on the engines - I'm guessing its not there yet?

Also, whats the cost to cleanup a wreck like that vs the added "efficiency" from maxing out the train?  In the IT world, we do a Business Impact Analysis then both quantitative and qualitative assessments - for example - I choose not to buy a malware program that costs $1000 for my 100 computers. Assume that it's 100% effective.  If I have 1 incident per month, and it takes the system admin 1 hour per machine to restore it, you can quickly see that it's worth while to spend the $$$



Just curious

For the most part these days, train makeup is based on minimizing switching instead of good train handling.  There are a number of rules when it comes to train makeup, but when following those rules there are many ways to build a train and still comply, so you can build a train that meets the requirements of the rules but is still built to make train handling a nightmare.

The Energy Management Systems (LEADER AND TRIP OPTIMIZER) are somewhere between cruise control and self driving software in cars.  Keeping the train at track speed on clear signals on level track, they do just fine, but when forced to make decisions about train handling in tricky territory they are pretty bad.

Railroad management really doesn't take a long term vision approach to operations, but more of what can I do to benefit me right now.  Additionally, consequences are given little consideration because most of the time, no matter what stupid/sketchy plan management comes up with, the crews find a way to make it work.  You might ask why crews would try to make risky decisions on the part of management work?  Because they are threatened with they're job if they don't.  I'd be willing to bet that when the crew was told to back that train down the hill and they voiced their concern, the first question the crew was asked by management was "Are you refusing service"?

Scott
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Spades

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Re: Tehachapi Derailment
« Reply #17 on: January 31, 2023, 09:22:05 PM »
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I thought the problems with trains in the western US was mountains/grades and long trains.  The locomotive pulling the train has first half of the train pushing the locomotive(down grade) and the rear half is pulling on the train (upgrade).