In response to reports of intercom failures and a request from the Tri-Oversight Committee to investigate, Metro railcar engineers have identified the root of the problem with the on-board intercom systems not functioning on certain trains.
According to Metro’s website, the intercom systems do not work properly when 6000-series railcars are the lead car. When the 6000-series cars are in front, the intercoms in 1000-series or 4000-series cars on the back-end do not work.
"Now that the issue has been identified and verified by engineering staff, we are taking appropriate action to immediately mitigate the situation and resolve it as quickly as possible," said General Manager and CEO Richard Sarles.
Sarles called for the following actions on Tuesday:
1.) Railcars must be immediately realigned to ensure the 6000-series are not in front of 1000-series or 4000-series cars until the technical problems were fixed.
-Metro workers completed the task overnight. All trains were cleared by Wednesday.
2.) The Metro staff must take all necessary actions appropriate to expedite the process including working overtime.
-In order to fix the technical issues dealing with 1000-series trains, new control panel components must be installed in the 184 cars of the 6000-series group. Metro has installed the parts in the first 20 cars and plans to reach the remaining cars in the next 45 days.
-In order to fix the technical problems dealing with the 4000-series, the cars need a software update. A time period to complete this action hasn’t been determined yet.
3.) Metro safety officers are to conduct random sport-checks of the intercom systems while the train is in service.
-Spot-checks started on Wednesday. Trains with intercom systems that did not work were to be removed from service.
4.) Metro is to thoroughly review the diagnostic process to determine if the issue could have been detected sooner.
-The results of the review will be shared with the Board Safety and Security Committee during a public session.
Railcar intercom signals are transmitted from one car to another through the “train-line” cable. The cable has the audio for PA announcements and intercoms, the open and close door electronic commands and the LED signs data.
Engineers identified that the current levels were too low on the 1000-series intercoms. This prevented the signal from being recognized when the 6000-series car was leading. Certain electronic boards inside the 6000-series communication control panel would have to be replaced in order to fix the issue. The replacements include different resistors that allow the 6000-series control panel to recognize the current levels of the 1000-series car intercoms. The software in the 4000-series cars also have problems communicating with the 6000-series railcars.