positive train control
アメリカのニュージャージー州ホーボーケンの駅に制限速度を大幅に越した電車が突っ込み、100人以上が負傷し、女性が１人亡くなりました。
Could positive train control have prevented NJ accident?
The deadly crash of a New Jersey Transit train Thursday underscores the need for a critical speed-control system on America's railways, according to industry experts.
National Transportation Safety Board Vice Chairman Bella Dinh-Zarr said part of the crash investigation will focus on positive train control. The safety system combines GPS, wireless radio and computers to monitor trains and stop them from colliding, derailing or speeding.
If a train isn't being operated in accordance with signals, speed limits or other rules, the system automatically slows or stops it.
"That is absolutely one area that we always look into for every rail accident," Dinh-Zarr said of the technology.
The morning rush-hour crash killed at least one person and injured more than 110 others.
New Jersey Transit has not installed PTC, though it does have an older safety system.
Congress originally required the newer technology to be operational by the end of 2015. It extended the deadline to the end of 2018 to avoid a possible shutdown of the nation's railroads.
"Every PTC-preventable accident, death, and injury on tracks and trains affected by the law will be a direct result of the missed 2015 deadline and the delayed implementation of this life-saving technology," NTSB
Chairman Christopher Hart said earlier this year.
But officials urged there be no rush to judgment on the circumstances.
http://edition.cnn.com/2016/09/29/us/new-jersey-hoboken-train-safety/index.html
今回取り上げるのはpositive train controlです。
positiveときくと「前向きな、ポジティブシンキング」など浮かびがちですが、ここでは少し違った使い方がされています。
この記事や、Association of American railroadというサイトでも“a set of highly advanced technologies designed to make freight rail transportation—already one of the safest U.S. industries—even safer by automatically stopping a train before certain types of accidents occur. In 2008”と定義されているように、ここでのpositiveは「自動的な」といったニュアンスが感じられます。おそらくは最近，流行りのproactive，つまり機械が積極的に介入する「予防安全の」のような意味合いでしょうか。
事故の詳しい原因はまだ分かっておらず、車両故障の可能性や運転手から事情聴取を行うなどして調査を進めています。(flyingbird)
