News Q & A: Safety

Spanish

Safety of the Metrorail system

Automatic Train Operation (ATO)

Track circuits

NTSB recommendations

Metro operations and policies

Safety of the Metrorail system

How safe is the Metrorail system?
Despite the tragedy of the June 22 collision, in which eight passengers and the train’s operator died, our Metro system is among the safest in the nation. We are cooperating with the NTSB’s investigation, and working closely with the Tri-State Oversight Committee, American Public Transportation Association and other organizations to make our system as safe as possible.

What steps is Metro taking to ensure the safety of the Metrorail system?
Metro is taking action on the urgent safety recommendation the NTSB issued to Metro on July 13 to enhance the safety redundancy of the train control system by using real-time data to detect losses in track occupancy and automatically generate alerts.

Metro is taking additional steps to ensure the safety of the Metrorail system:

  1. All Metrorail trains are being manually operated by train operators and will continue until further notice.
  1. Metro has inspected all of its 3,000 signaling circuits throughout the Metrorail system to ensure they are sending the correct signals between the trains, tracks and the Operations Control Center.
  1. Metro is running twice-daily computerized tests of the circuits, once after each rush hour, or 14 times per week.
  1. Metro plans to replace the 1000-series rail cars as soon as funding is available.
  1. Metro has contacted external experts in track signaling and circuitry from across the country to help determine what may have caused last month’s train collision. This effort includes the American Public Transportation Association and an independent review of critical components such as signals and circuitry.
  1. Metro is working with an existing contractor, ARINC, and other outside vendors on developing a real-time monitoring system that would detect circuit failures and generate alerts.
  1. Metro will continue to devote significant resources in preparation to promptly implement NTSB’s recommendations.

Who has safety oversight for Metro?
There are several levels of safety and security oversight by federal government agencies, a regional authority and through the North American transit industry. The oversight entities include:

  1. Federal Transit Administration (FTA): provides an extensive program of technical assistance and withholds grant funds for noncompliance with conditions of grants (including safety requirements).
  1. National Transportation Safety Board (NTSB): investigates the probable cause of railroad accidents involving passenger trains or any train accident that results in at least one fatality or major property damage.
  1. Tri-State Oversight Committee (TOC): state safety oversight entity (as mandated by law and FTA rules) created in 1997 through an MOU by the District of Columbia, State of Maryland and Commonwealth of Virginia
  1. American Public Transportation Association (APTA), a professional trade organization: Through its Safety Management Audit Program, APTA develops and implements a standardized format for rail system safety and provides an auditing service to determine the degree to which the standardized elements for rail transit system safety were being addressed.
    top

 

Automatic Train Operation (ATO)

What is Automatic Train Operations (ATO)?
Automatic Train Operations is a system that Metro has been using since the Metrorail system opened in 1976 to operate its Metrorail trains during rush hours and other times of day.

Throughout the Metrorail system, automatic train control rooms house vital electronics that assist in the movement of trains. The train control rooms send electronic signals to the tracks, which in turn, send signals into devices located between the tracks. When a train operates over one of these devices, the device relays that signal to the train in the lead car, and provides critical information to the train. These signals are also sent to the train even when the train is in manual operation.

Metro trains also are operated manually by train operators, usually during non-rush hours and whenever track maintenance is being performed and track workers are in a specific area of the track. As a precaution, Metrorail trains are currently being operated manually by train operators until further notice.

Did a problem with Metro’s Automatic Train Operation (ATO) cause the accident?
The National Transportation Safety Board (NTSB) is the lead agency that investigates the cause of accidents like this one. Its investigation, which may take many months, will determine the cause of the collision and make recommendations.

Metro has been using Automatic Train Operations to operate its Metrorail trains during rush hours and other times of day since the Metrorail system opened in 1976. As a precaution, Metrorail trains currently are being operated manually by train operators until further notice.

How does the train operator know the train is in ATO?
The train operator controls the mode of operation for the train and can switch between manual and ATO.

Does the train operator have to be in manual mode to activate the emergency brake?
The emergency brake can be activated in either manual or ATO.

Why was Metro’s Superintendent of Automatic Train Control reassigned shortly after the accident?
It is standard operating procedure for any Metro employee directly involved in an accident to be temporarily reassigned or relieved of their duties while there is an investigation underway

Metro’s Superintendent of Automatic Train Control was reassigned to a special project shortly after the accident. He returned to his regular duties on Monday, July 27.
top

Track circuits

What are track circuits?
Track circuits are electrical circuits that are part of a signal system that sends information, authorization and speed commands between the track and Metrorail trains. The circuits detect the presence of other trains and provide information that is used to maintain safe distances between trains. Track circuits are located on the tracks and in train control rooms.

Did a problem with Metro’s track circuits cause the accident?
The National Transportation Safety Board (NTSB) is the lead agency that investigates the cause of accidents like this one. The agency has issued updates about its investigation and reported that a track circuit where the accident occurred periodically lost its ability to detect trains several days before the accident.

Since the accident, Metro began conducting a twice-daily analysis of a computer-generated report to ensure that all circuits are operating within more stringent requirements. Engineers review computerized reports after each rush hour and investigate every anomaly they see.

Metro is working with an existing contractor, ARINC, and other outside vendors on developing a real-time monitoring system that would detect circuit failures and generate alerts.

Why didn’t Metro do something about the track circuit that was intermittently failing between June 17 and 22?
Repair work was done on this circuit on June 17 and was tested to ensure that it was working properly. At the time it was tested, all indications were that the circuit was working properly.

Since the accident, Metro began conducting a twice-daily analysis of a computer-generated report to ensure that all circuits are operating within more stringent requirements. Engineers review computerized reports after each rush hour and investigate every anomaly they see.

Metro is working with an existing contractor, ARINC, and other outside vendors on developing a real-time monitoring system that would detect circuit failures and generate alerts.

What indicators are there to show when a track circuit is not functioning properly? Are there alarms?
Although train controllers in Metro’s operations control center can receive some indications when circuits are malfunctioning, the specific problem identified in the area of the accident did not provide an indication that would have been easily detectable to controllers in our operations control center.

What is Metro doing to prevent a similar problem with other track circuits?
Since the accident, Metro began conducting a twice-daily analysis of a computer-generated report to ensure that all circuits are operating within more stringent requirements. Engineers review computerized reports after each rush hour and investigate every anomaly they see.

Metro is working with an existing contractor, ARINC, and other outside vendors on developing a real-time monitoring system that would detect circuit failures and generate alerts.

Is Metro planning to replace its signaling system? 
Metro will take whatever action is necessary to ensure the safety of the Metrorail system. 

What is an impedence or Wee-Z bond?
Wee-Z bonds are part of a signal system that sends information, authorization and speed commands between the track and Metrorail trains. Wee-Z bonds detect the presence of other trains and automatically transmit speed signals to a train as it passes over the Wee-Z bond, depending on the location and speed of other trains in the area. If one train enters a portion of track where another train has been detected to be in front of it, then the Wee-Z bond sends a signal that causes the following train to stop.

Did Metro know there was a problem with a Wee-Z bond for the track circuit where the accident occurred?
Metro normally conducts computerized analytical tests on a monthly basis to review what’s taking place electronically in the rail system. During a special review of the data after the accident, Metro discovered that a newly installed Wee-Z bond in the area of the accident periodically lost its ability to detect trains five days before the accident.

The intermittent performance of a Wee-Z bond would be extremely difficult to detect by controllers in Metro’s operations control center. Since the accident, Metro has increased the frequency of its track circuit data review from once every 30 days to twice daily (14 times per week) and is doing a deeper level of analysis with more stringent requirements. Engineers review computerized reports after each rush hour and investigate every anomaly they see.

How do you know other Wee-Z bonds and track circuits throughout the Metrorail system are safe?
Since the accident, Metro began conducting a twice-daily analysis of a computer-generated report to ensure that all circuits are operating within more stringent requirements. Engineers review computerized reports after each rush hour and investigate every anomaly they see.

Have there been other incidents in which the Automatic Train Control System failed to maintain a large distance between trains?
In 2005, there was an event in which three trains came very close to each other. The cause of that incident was determined to be cabling in the track circuit, below the track bed. In the current investigation of the June 22, 2009 accident, the NTSB is focused on track circuit modules in a train control room in its investigation of the cause of the collision. The train control room is some distance from the actual tracks.

On June 7, 2005 just after 6 p.m., a track circuit problem was identified in the tunnel between Foggy Bottom and Rosslyn Metrorail stations on the Orange/Blue Line. A train had stopped and second train came within 30 feet of the first, and a third train came to within 30 feet of the second. A news release was issued. As a precaution, trains were placed in manual mode between the two stations. About a week later, in a news release, officials identified the source of the track circuit problem as a defective 3,000-foot communications cable (part of the track circuit system) between those stations, 135 feet underground. The cause of the 2005 incident between Foggy Bottom and Rosslyn was determined to be a failure of a track circuit (C2-111) cable. Two trains were not receiving normal commands to reduce speeds when approaching a train in that track circuit. To correct the problem, the following components for that track circuit were replaced:

 

  • Track circuit cables for the receiver and transmitter impedance bonds,
  • The connecting wires from the track circuit cable entrance point to the receive and transmit modules
  • The audio frequency transmitter module
  • Receiver modules

In addition, three audio frequency circuits (C2-111, C2-106 and C2-121) were adjusted.

As part of the incident investigation, the track modules, the impedence bonds, and their connecting cables were examined in a lab, under microscope, for cable connection faults immediately following removal. Additionally, ALSTOM and Metro engineers jointly conducted a detailed review and determined that the probable root cause of the issue was a shorting of two wires in the bond line cables, which caused the track circuit to appear unoccupied. The work with Metro and ALSTOM engineers was completed in September 2005.

Additionally, Metro’s track circuit cable standards were upgraded. Specifically this had to do with the space/distance between cables and ensuring ample space between cables.

Metro also created the computerized tool for detecting loss of shunt incidents, or incidents in which a train is not detected. The tool was used weekly to monitor track circuit performance for one year. As the tool had not identified and serious problems in that time, it seemed reasonable to use the tool monthly after July 2006. Since the June 22, 2009 accident, the tool has been used twice a day to monitor track circuits.

As part of the NTSB investigation of the June 22, 2009 Red Line accident Metro has provided the NTSB all reports on the 2005 incident as well as the track modules that were replaced. The NTSB has yet to announce the root cause of the 2009 accident.

After the incident, were any safety recommendations made? Has there been oversight on this from the Tri State Oversight Committee (TOC)?
The Metro Office of Safety made six recommendations, and also provided information to the Tri-State Oversight Committee (TOC), which placed it on a list of incidents requiring action. Metro implemented these recommendations and the incident was removed from that list. The TOC recently put the incident back on its review list.

Metro's Safety Office meets with the TOC face-to-face on a monthly basis. In addition, since July 2008, Metro developed a series of additional work sessions that are "topic-specific" meetings that take place to discuss and review specific subjects such as accident reports and action plans.

Since this effort began, Metro has closed out three-quarters of the outstanding issues, 144 of 192, with the TOC.

Office space was also made available for a member of the TOC to work in Metro’s Safety Office in an effort to improve progress in closing out various reports.

What were the six safety recommendations recommended as a result of the June 2005 incident?
The first recommendation was that Metro should evaluate the track circuit design to determine the extent to which current and future designs can be modified to prevent a recurrence of that type of failure.

This was done. Changes were made to our standard specification to improve the physical separation between cables of audio frequency track circuits.

The second and third recommendations were that Metro should continue to monitor track circuit behavior and formalize the process. To implement these recommendations, Metro created the computerized tool for detecting loss of shunt incidents, or incidents in which a train is not detected. Metro also created the computerized tool for detecting loss of shunt incidents, or incidents in which a train is not detected. The tool was used weekly to monitor track circuit performance for one year. As the tool had not identified any serious problems in that time, it seemed reasonable to use the tool monthly after July 2006. Since the June 22, 2009 accident, the tool has been used twice a day to monitor track circuits.

The cause of the 2005 incident was determined to be cabling in the track circuit, below the track bed. In the current investigation of the June 22, 2009 accident, the NTSB is focused on track circuit modules in a train control room in its investigation of the cause of the collision. The train control room is some distance from the actual tracks.

The fourth recommendation was that a rule should be created that requires train operators to immediately report to the Operations Control Center the use of emergency brakes, like those that were used during the 2005 incident. This rule was already in place in the 2004 rule book.

The fifth recommendation was that when an emergency brake is used to prevent a collision between trains, Metro should have procedures that call for the following:

 

  1. require all trains moving through the area of the incident to proceed only with the permission of a controller;
  2. take the incident train out-of-service at the next available station and ultimately take it off the rail line;
  3. take the Train Operator out-of-service;
  4. Report the incident to appropriate maintenance and engineering groups;
  5. document the event and conduct an investigation of the train and the ATC system.

These policies were already in place, and were reviewed as a result of the incident.

The sixth recommendation was that Metro should create a special reporting code for the use of brakes to prevent a collision between trains. A routine part of train or signal control incident investigations includes analysis of how brakes were applied during any given incident. That information is then entered into a computer system for tracking purposes.
top

NTSB recommendations

What is Metro’s response to the NTSB’s Urgent Safety Recommendation issued on July 13?
The NTSB issued an urgent safety recommendation to Metro on July 13 to enhance the safety redundancy of the train control system by using real-time data to detect losses in track occupancy and automatically generate alerts.

Metro is working with an existing contractor, ARINC, and other outside vendors on developing a real-time monitoring system that would detect circuit failures and generate alerts.

What actions did Metro take in response to the NTSB findings following Metrorail collisions in 1996 and 2004?
The 1996 collision at Shady Grove was primarily attributed to icy conditions and restrictive directives to the operations control center that mandated operations only in automated mode. In response, Metro clarified its standard operating procedures. These changes have prevented similar accidents under similar conditions.

The 2004 collision at Woodley Park was due to operator error and failure to follow standard operating procedures. Since the accident, Metro is working to comply with the NTSB’s recommendation to install rollback features in its rail cars.
top

Metro operations and policies

What kind of insurance does Metro have?
Metro has business property and casualty insurance. The transit agency carries multi-risk insurance on the transit system covering direct physical loss or damage and public liability insurance covering injuries to people and property. Metro is covered under a layered program with a number of insurance carriers.

Are Metro’s train and bus operators permitted to use cell phones or other electronic devices while operating Metro vehicles?
Metro has a new, zero tolerance policy for employee use of electronic devices while operating Metro vehicles, which was adopted on July 13. While operating Metro vehicles, electronic devices must be turned off and out of sight. Use of any electronic devices is strictly prohibited. Metrobus and Metrorail operators caught using a cell phone, texting or using a PDA while operating a vehicle will be fired on their first offense.
top

 

Return to Moving Forward on Safety web page


© 2013 Washington Metropolitan Area Transit Authority       Privacy Policy and Legal Disclaimer

   BrowseAloud icon