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Re: NTSB Press Release re: BNSF rear-end collision in Iowa
Author: SP5103
Date: 05-04-2011 - 17:29
> (d) Alerter warning timing cycle interval shall be
> within 10 seconds of the calculated setting
> utilizing the formula (timing cycle specified in
> seconds = 2400 ÷ track speed specified in miles
> per hour).
At 23 mph (as in the rear end collision being discussed), 2400/23 = 104 seconds (over a minute and a half). At 23 mph or about 34 feet per second, you have traveled about 3,508 feet in 104 seconds. According to the report: "The observers were able to identify the standing train about 1,376 feet from the point of collision."
A train at 10 mph could travel for 4 minutes before the alertor tripped. Regardless of speed, the train is going to travel about 3500-3600 feet between alerter resets. What until you get high speed rail at 125 mph (or on the NE Corridor), the alerter will have to be reset every 19 seconds per the formula - and that won't distract the engineer?
Even a fully functioning alerter under the proposed rule would not have prevented the accident. Anybody know how PTC will allow trains to close up at restricted speed?
> within 10 seconds of the calculated setting
> utilizing the formula (timing cycle specified in
> seconds = 2400 ÷ track speed specified in miles
> per hour).
At 23 mph (as in the rear end collision being discussed), 2400/23 = 104 seconds (over a minute and a half). At 23 mph or about 34 feet per second, you have traveled about 3,508 feet in 104 seconds. According to the report: "The observers were able to identify the standing train about 1,376 feet from the point of collision."
A train at 10 mph could travel for 4 minutes before the alertor tripped. Regardless of speed, the train is going to travel about 3500-3600 feet between alerter resets. What until you get high speed rail at 125 mph (or on the NE Corridor), the alerter will have to be reset every 19 seconds per the formula - and that won't distract the engineer?
Even a fully functioning alerter under the proposed rule would not have prevented the accident. Anybody know how PTC will allow trains to close up at restricted speed?
