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Wrong side failure of a set of boom barriers in Utah

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Re: Wrong side failure of a set of boom barriers in Utah

Unread postby S&TEngineer » Tue Jan 31, 2017 11:10 am

A short update from UTA: https://www.rideuta.com/About-UTA/For-t ... k-Accident
UTA Releases Preliminary Information About Incident Between FrontRunner and FedEx Truck

Jan. 24, 2017—Preliminary investigation results, including police video of the Jan. 21 accident between a FrontRunner train and a FedEx cargo truck in North Salt Lake, indicate that the crossing gates were in the up position, and the flashing lights and bells were not activated at the time of the incident.

In the event of a power outage or lack of signal, crossing gates are programmed to default to the “down and active” position as a safety precaution. Preliminary information indicates the gates were affected by the severe ice and snow conditions at the time and were in the default “down and active” position, as they are programmed. After an employee responded to the location, the gates moved to the up position. The agency has never had an accident like this before, and UTA is investigating why and how it happened to ensure it doesn’t occur again.

UTA has well established investigation protocols, and has initiated a thorough investigation of all systems and is conducting interviews with employees to identify whether all protocols and procedures were followed to ultimately determine the cause of the incident and whether human error was a factor.

Appropriate safety oversight agencies and officials have been notified and are monitoring UTA’s investigation. Following completion of the investigation, all appropriate actions will be implemented to prevent this from happening in the future.

UTA is grateful there were no serious injuries in the accident. Safety is the agency’s top priority, and we are committed to a thorough and accurate review of this incident to ensure we are providing a safe transit system to our customers.
Regards,
S&TEngineer
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Out of this nettle, Danger, we pluck this flower, Safety.
Henry IV, Part 1, Act 2, Scene 3
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Re: Wrong side failure of a set of boom barriers in Utah

Unread postby Mad Mac » Tue Feb 21, 2017 6:01 am

As someone who works on the US transit systems after 20+ years on BR, I think I can provide some background.

This crossing is, to all intents and purposes, an AHB - on a non-electrified line such as this, what's used is a "predictive" system where the change of impedance in the rails is used to determine how fast a train is approaching and (in theory) give the same warning time (typically 20 seconds) irrespective of how fast the train is approaching. If an approaching train stops, the crossing will de-activate once the system "realises" it's stopped and will then reactivate once the train gets on the move again.

The logic, be it relays or a processor-based system, is generally simple: approach track, "island" track (the actual crossing area - occupying this one will activate the crossing no matter what) and exit track. However, if a train doesn't clear the "exit" track and comes back the way it came, the crossing won't activate because the directional logic hasn't reset itself. Not wishing to speculate too much, but there's what may be a maintenance truck parked just beyond the crossing. Another interesting thing is that the crossing activates 30 seconds after the train first enters it.
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Re: Wrong side failure of a set of boom barriers in Utah

Unread postby Mike Hodgson » Tue Feb 21, 2017 12:45 pm

Are US railroad accidents subject to investigation by an independent body - or does the railway merely conduct its own investigation and report its findings to some regulator? That UTA release implies that the weather had caused a "power outage or loss of signal" necessitating an S&T call - and the video clip shows what appears to be an electricity supply on pole route at the crossing, so the mains feed may well have been vulnerable to weather.

Although the UTA "preliminary" press release indicates that they were still conducting interviews they nevertheless made strong hints to the effect that their technician had acted in some way incorrectly in raising the barriers after failure, and it sounds very much as though the company is passing blame onto its employee before completion of the investigation into what he did and why.
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Re: Wrong side failure of a set of boom barriers in Utah

Unread postby Danny252 » Tue Feb 21, 2017 1:34 pm

The National Transport Safety Board is the federal agency who would produce such accident reports, but the number of incidents investigated is comparable to the RAIB - the NTSB reports 10 ongoing "major" investigations that are rail-related, compared to the RAIB's 16 listed ongoing investigations. The NTSB website doesn't make it clear as to whether this is all investigations; it is stated that "most [investigations] occur at the regional level", but the regional listings only cover aviation accidents, and certain pages imply list of 10 covers "all Railroad investigations".

The Federal Rail Administration also collect accident reports, but that appears to be just for statistical purposes (perhaps the NTSB/FRA split is comparable to RAIB/ORR).
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Re: Wrong side failure of a set of boom barriers in Utah

Unread postby madscientist » Tue Feb 21, 2017 5:53 pm

I do t claim to understand US signalling ( or lack of it ) , surely there is railway based signalling on either side of the AHB, that is triggered by the physical act of the barrier coming down and if it didnt the train has an appropriate warning to stop. crossing only barriers without being interlocked to approach signalling would seem to be way less then satisfactory
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Re: Wrong side failure of a set of boom barriers in Utah

Unread postby Mad Mac » Tue Feb 21, 2017 7:18 pm

It's not radically different to the U.K. If you have an AHB in the middle of an Absolute Block section with no signal in the vicinity, then there's nothing to stop a train if the barriers stay up for some reason. Thing is, the barriers generally don't stay up with a train approaching. As I explained it to someone about 20 years ago: at the end of the day, it's a balance of probabilities.
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Re: Wrong side failure of a set of boom barriers in Utah

Unread postby Mad Mac » Fri Feb 24, 2017 11:29 pm

Without going into too much detail, I understand from my sources in the industry here that there was no equipment malfunction involved. The "official" NTSB report typically takes around a year to appear.
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