Oh, now they think it's a good idea

Bloomberg.com has an article by Angela Greiling Keane about banning the use of mobile phones by railroad crews:

The Federal Railroad Administration announced the ban today. The move follows a Los Angeles commuter- train crash on 12 September that the National Transportation Safety Board said happened seconds after the engineer sent a text message. While most railroads have rules and procedures that restrict use of electronic devices the measures haven't been effective.
The head-on collision between the commuter train and a Union Pacific Corp. freight train killed 25 people, making it the deadliest U.S. passenger rail accident in 15 years, according to the NTSB. Metrolink, the Los Angeles-area commuter service involved in the crash, already banned its engineers from using electronic devices in locomotive cabs before the accident.
The Federal Railroad Administration said other accidents this decade may have been caused by rail employees using such devices, including one in June in which a Union Pacific worker was struck and killed by a train after walking behind it while talking on his phone. The regulator listed six other freight railroad accidents, including some that were fatal, dating back to 2000 that involved mobile-phone use.