Tag Archives: metro train

Root Cause Analysis - Incident Investigation

Chicago O’Hare Commuter Train Derailment Injures 33

By Sarah Wrenn

At 2:49 AM on March 24, 2014, a Blue Line Commuter train entered the Chicago-O’Hare International Airport Station, collided with the track bumper post, and proceeded to derail landing on an escalator and stairway.  Thirty-two passengers and the train operator were injured and transported to nearby hospitals.  Images showing the lead rail car perched on the escalator look like the train was involved in filming an action movie.

So what caused a Chicago Transit Authority (CTA) train, part of the nation’s second largest public transportation system, to derail?  We can use the Cause Mapping process to analyze this specific incident with the following three steps: 1) Define the problem, 2) Conduct the analysis and 3) Identify the best solutions.

We start by defining the problem.  In the problem outline, you’ll notice we’ve asked four questions: What is the problem? When did it happen? Where did it happen? And how did it impact the goals?

Next we’ll analyze the incident.  We start with the impacted goals and begin asking “why” questions while documenting the answers to visually lay out all the causes that contributed to the incident.  The cause and effect relationships lay out from left to right.  As can be seen in the problem outline, this incident resulted in multiple goals being impacted.

In this incident, 33 people were injured when the train they were riding derailed in the O’Hare station thereby affecting our safety goal of zero injuries.  The injuries were caused by the train derailing, so let’s dig in to why the train derailed.  Let’s first ask why the train operator was unable to stop the train.  Operator statements are crucial to understanding exactly what happened.  Here, it is important to avoid blame by asking questions about the process followed by the operator.  Interestingly, 45 seconds before the crash, the operator manually reduced the train speed.  However, at some point, the train operator dozed off.  The train operator’s schedule (working nearly 60 hours the previous week), length of shift, and time off are all possible causes of the lack of rest.  Evidence that the operator was coming off of an 18 hour break allows us to eliminate insufficient time off between shifts as a cause.  In addition, the train operator was relatively new (qualified train operator in January 2014), but also she was an “extra-board” employee meaning she substituted for other train operators who were out sick or on vacation.

Next, let’s ask why the train was unable to stop.  An automatic breaking system is installed at this station and the system activated when the train crossed the fixed trip stop.  The train was unable to stop, because there was an insufficient stopping distance for the train’s speed.  At the location of the trip stop, the train speed limit was 25 mph and the train was traveling 26 mph.  While the emergency braking system functioned correctly, the limited distance and the speed of the train did not allow the train to stop.

The train derailing impacted multiple organizational goals, but also the personal goal of the train operator who was fired.  During the investigation, we learn that the train operator failed to appear at a disciplinary hearing and had a previous safety violation in which she dozed off and overshot a station.  These details reveal themselves on the cause map by asking why questions.

The final step of the investigation is to use the cause map to identify and select the best solutions that will reduce the risk of the incident recurring.  On April 4, 2014, the CTA announced proposed changes to the train operator scheduling policy.  In addition, the CTA changed the speed limit when entering a station and moved the trip stops to increase the stopping distance.   Each of these identified solutions reduce the risk of a future incident by addressing many of the causes identified during the investigation.

Root Cause Analysis - Incident Investigation

Metro Train Derails in the Bronx, Killing 4 and Injuring More Than 60

By Kim Smiley

Four passengers were killed and dozens more sent to the hospital after a metro train derailed in the Bronx early Sunday, December 1, 2013.  At the time of the accident, the train was carrying about 150 passengers and was traveling to Grand Central Terminal in New York City. The aftermath of the accident was horrific with all seven cars of the commuter train derailing. Metro-North has been operating for more than 30 years and this was the first accident that resulted in passenger deaths.

A Cause Map, or visual root cause analysis, can be built to help analyze this accident.  There is still a lot of investigative work that needs to be done to understand what caused the derailment, but the information that is available can be used to create an initial Cause Map.  The Cause Map can easily be expanded later to incorporate more information as it becomes available.  The first step when building a Cause Map is to fill in an Outline with the basic background information.  The impacts to the goals are also documented on the bottom of the Outline.  The impacted goals are then used to begin building the Cause Map.

In this example, the safety goal is clearly impacted because there were four fatalities and over 60 people injured.  The schedule goal is also significantly impacted because this portion of rail will be closed during most of the investigation.  The National Transportation Safety Board has estimated that the investigation will take 7 to 10 days.  The track closure is particularly impacting because this is a major artery into New York City with a ridership of 15.9 million in 2012.  Once the impacted goals are documented, the Cause Map itself is built by asking “why” questions.

So why did the train derail?  The details aren’t known yet, but there is still some information that should be documented on the Cause Map.  A question mark is included after a cause that may have contributed to an issue, but requires more evidence or investigation.  It’s useful to document these open questions during an investigation to ensure that all the pertinent questions are asked and nothing is overlooked.  (If it is determined that a cause didn’t play a role, it can be crossed out on the Cause Map to show that the cause was considered, but ruled out.)  Two factors that likely  played a role in the derailment are the speed of the train and the track design where the accident occurred.  There is a sharp curve in the track where the derailment happened.  Trains are required to reduce their speed before traveling it.  The latest reports from the investigation are that the train was traveling 82 mph in a 30 mph zone. The train operator has stated that the brakes malfunctioned and didn’t respond when he tried to reduce speed and that the train was traveling too fast over the curved track.

Investigators have recovered the data recorder from the train which will provide  more information and if there was a problem with the brakes.  Investigators will also interview all the relevant personnel and determine what happened to cause this deadly crash.  Once the investigation is completed, any necessary solutions can be implemented to reduce the risk that a similar accident occurs in the future.

To view a completed Outline and initial Cause Map of this incident, click on “Download PDF” above.