NTSB to railroad industry: Automated systems can’t replace humans
The National Transportation Safety Board (NTSB) has issued urgent safety recommendations to the Federal Railroad Administration, the Association of American Railroads, the American Short Line and Regional Railroad Association, and the American Public Transportation Association to help ensure that electronic alertness devices or “alerters” work as intended on trains.
Alerters have limits
The alerter helps crew members maintain vigilance in the locomotive cab by monitoring locomotive engineer activity. If it has been too long since the locomotive engineer performed an input or action to reset the alerter, the system issues visual and audible alerts, and applies train brakes if there are still no inputs from the crew. However, the agency found, an alerter’s reckoning of “idle time” can be reset to zero by inputs that do not necessarily demonstrate a crew member’s continuing engagement.
“The alerter is an automated system to make sure the human is engaged and, if necessary, to take action,” said NTSB Acting Chairman Christopher A. Hart. “We found that the alerters were acting from automated events as if they had been human inputs.”
Fatal accident revealed issue
The NTSB discovered this safety issue and issued urgent recommendations as a result of the ongoing investigation of the 2014 collision of two Union Pacific freight trains, one southbound and one northbound, in Hoxie, Arkansas. The accident resulted in the deaths of two crewmembers, the derailment of 55 cars, a release of diesel fuel, a fire, and the evacuation of about 500 nearby residents.
The southbound train was equipped with a horn sequencer. The horn sequencer is activated with a single push of the sequencer foot pedal under the engineer’s control console. Once activated it continually sounds the cadence for approaching a highway-rail grade crossing – a series of two long sounds, one short sound, and another long sound -- until the sequencer foot pedal is again depressed.
NTSB’s examination of the southbound train’s event recorder noted that the horn sequencer reset the electronic alertness device each time the horn blew, as if the locomotive engineer were commanding each sound manually. This prevented the device from providing an alarm to the train crew or activating the brakes.
While the NTSB has not yet reported the accident’s probable cause, the agency issued these urgent recommendations to address the safety issue that came to light during the investigation.
“The Union Pacific railroad has moved to fix this problem. The FRA needs to require that other railroads understand the problem and fix it where it is necessary,” said Hart.