Eight trains so far in 2016 have run past red signals on the Metrorail system. On July 5th, two trains ended up facing each other (though still a fair distance apart) on the same tracks, and on July 13th a train at National Airport stopped past the end of the center platform at the station. Nobody was injured in either incident, but the trend is troubling.
Near-collision near Glenmont
Around 7:15 pm on the 5th, a Red Line train leaving Glenmont and traveling towards Wheaton ran a red signal, went the wrong way over a switch, and ended up facing south on the same track that a train headed north toward Glenmont was on. The incident showed how the Automatic Train Control system can help prevent crashes, but also showed how human factors can still trump technology.
The incident train, train 121, was at Glenmont facing south toward downtown, and was waiting at a red signal to go the “wrong” direction on the outbound track to cross over and continue back to Wheaton. Train 125, which had departed Wheaton towards Glenmont, also on the outbound track, was set to approach the station and cross over from the outbound track to the inbound track, and berth on the inbound platform at Glenmont.
The operator of train 121 left Glenmont, bypassing a red signal, and without permission. Since the switches outside Glenmont were set for the incoming train 125 to cross over, the outgoing train (121) trailed one of the switches in the interlocking, meaning that the train went over the switch in the opposite direction that it was set. This can cause damage to the switch and sometimes requires repair, like what happened in February when an Orange line train ran a red signal and trailed a switch outside the Smithsonian station. I requested damage information from Metro regarding the Glenmont incident, but never received a reply.
When train 121 ran the red signal, it entered an Automatic Train Control (ATC) block which it didn’t have permission to be in; this triggered an alarm at the Rail Operations Control Center (ROCC), calling their attention to the train. The ATC system is designed to ensure that a safe distance is maintained between all trains at all times and because of this, it would have dropped speed commands (like a speed limit on the highway) to 00 (zero) for the block or blocks in front of train 121. Giving any train near train 121 zero speed commands would cause them to stop and help prevent, or at least minimize, chances of a collision.
So if the ATC system was giving trains in the area 00 speed commands — including train 121 — why was it still able to move? The train was operating in manual mode (Mode 2), meaning that the train operator controlled the speed of the train with their hand on the Master Controller, sort of similar to a combined gas and brake pedal. The train was not in Automatic Train Operation (ATO) mode, in which the train would automatically speed up and slow down as necessary (in fact, no train currently is operating in ATO).
Since the train was in manual mode, it was allowed to travel at up to but not exceed 15 miles per hour, even after passing a red signal. When passing the signal the train’s Automatic Train Protection (ATP) system would cause it to come to a complete stop, but the operator would be able to continue moving it at up to the 15 mph limit.
Being able to operate at up to 15 mph past a red signal isn’t the typical operating procedure, but does happen from time to time on the rail system. This mode of operations, which essentially means that the ATC system is being ignored, is used when trains are given “absolute blocks.” That’s when the ROCC, like an old-school train dispatcher, manually gives trains permission to pass through a stretch of track at up to that 15 mph limit. This also means that only one train is allowed through that stretch at any given time, for safety.
Metro general manager Paul Wiedefeld fired the operator of train 121 that ran the red due to the “blatant disregard for safety” and the risk they created for their coworkers.
Red signal violation at National Airport
The incident on July 13th occurred at the National Airport station, which is the north-most station of the “cut-off” portion of the Blue and Yellow lines during SafeTrack’s Surge 4. All Blue and Yellow trains to and from Franconia and Huntington, respectively, berth at the station, unload and reload passengers, and leave on out. According to Metro, the Yellow Line train involved in the incident entered the center track of the station at a slow speed, and ended up about half a train car beyond the end of the platform, past a red signal.
The National Airport station includes one of the system’s few “pocket tracks,” a third track between the two main tracks in which a train can be re-routed or stored. On either end of the pocket track is a switch which can be aligned to send the train to either of the two main tracks. A train in the pocket track could turn out to either track leading to Huntington/Franconia on one end, or to either track leading to New Carrollton/Largo. The tracks give Metro a lot of flexibility, as they can be used during single-tracking to store trains or equipment, or to help turn trains around.
Since there are switches at either end of the pocket track leading to the two main tracks, there are also signals to tell train operators what they can do, which Matt’ Johnson detailed after the Fort Totten crash. At a solid white lunar signal, the train operator can proceed straight through the switch down the track. At a flashing white lunar, the switch is set to cross the train over to another track. And at a red signal, the train operator cannot pass the signal (in this case, cannot pass through the switch) unless given permission by the ROCC.
A safety feature that Metro has installed at almost all pocket tracks is a derail, a device that can intentionally cause a train’s wheels to come off of the track, in order to keep it from entering another track. In February 2010, one of these derails kept a Red Line train from exiting the pocket track near Farragut North when it had a red signal. At National Airport, the derail device sits at the north end of the pocket track on the right rail, just before the switch that the signal on the north end governs.
In this photo, the derail is shown in yellow on the left side of the right rail, near the rectangular box (a switch control box) on the right side of the rail:
When engaged, a train’s wheel will roll up the derail, and off the side of the track, disabling the train. However at National Airport, since a red signal would have been displayed for all three tracks and no trains were being allowed north into the SafeTrack area, the derailer was not engaged. While this meant the train didn’t need to be re-railed, it also means that if the train were to have continued onto one of the two mainline tracks and another train were to run a red signal on that main track (very remote odds that both of these happen at the same time, I know), a collision could have happened.
Just like a car shouldn’t enter an intersection at a red signal and a plane shouldn’t enter a runway without permission, a train shouldn’t run a red signal without permission. There’s been research into why operators continue to run the signals, and the Federal Transit Administration is collecting data from rail systems across the US to better understand how common the occurrence is, but the number of times it happens should never be higher than zero.