Click on "Full screen" for a more comfortable reading experience, then click on the cross to close this window. Click on the questions that appear at the top of the screen to reveal all the content before clicking on "Continue". Follow all the steps in order before reaching the summary.
WHY did the rear car derail?
The switch was defective
Speed was excessive
To be explored in step 2
WHY?
The reporting wasn't followed by sufficient corrective action
WHY?
The corrective maintenance was not given priority
WHY?
The maintenance team was mobilized on another switch
WHY?
Spare parts for the switch were not available
ROOT CAUSE #1
Cause #2
WHY did the rear car derail?
Speed panel was hidden by vegetation
The driver had not received the information
To be explored in step 3
WHY?
Driving-at- sight not well applied
To be explored in step 4
No action was taken by the maintenance services despite a report 2 days before by a driver
WHY?
The outgoing dispatcher did not give clear instructions during the changeover
WHY?
The outgoing dispatcher was in a hurry to finish his shift
ROOT CAUSE #2
Cause #3
PREVIOUS
WHY had the driver not received any information about the Temporary Speed Limit?
No safety notice for drivers was available when they took up duty
ROOT CAUSE #3
Cause #5
The OCC did not see fit to remind drivers of the speed limit
ROOT CAUSE #4
PREVIOUS
WHY did the driver misapply the speed limit?
He was distracted by his phone
He didn't understand the "driving-at-sight" rule
WHY?
ROOT CAUSE #5
He was tired and stressed
He had not turned off his personal phone
ROOT CAUSE #6
ROOT CAUSE #7
IN SUMMARY
Track unit not repaired BECAUSE spare parts not available
Speed panel masked BECAUSE signal transmitted incorrectly by a dispatcher in a hurry to finish his shift
Information poorly transmitted to driver BECAUSE no safety note or information from OCC
Driving-at-sight not applied correctly BECAUSE practice poorly understood + driver fatigue, stress and distraction
PRÉCÉDENT
C3N4 - 5 Pourquoi EN
SD team
Created on March 9, 2026
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Transcript
Click on "Full screen" for a more comfortable reading experience, then click on the cross to close this window. Click on the questions that appear at the top of the screen to reveal all the content before clicking on "Continue". Follow all the steps in order before reaching the summary.
WHY did the rear car derail?
The switch was defective
Speed was excessive
To be explored in step 2
WHY?
The reporting wasn't followed by sufficient corrective action
WHY?
The corrective maintenance was not given priority
WHY?
The maintenance team was mobilized on another switch
WHY?
Spare parts for the switch were not available
ROOT CAUSE #1
Cause #2
WHY did the rear car derail?
Speed panel was hidden by vegetation
The driver had not received the information
To be explored in step 3
WHY?
Driving-at- sight not well applied
To be explored in step 4
No action was taken by the maintenance services despite a report 2 days before by a driver
WHY?
The outgoing dispatcher did not give clear instructions during the changeover
WHY?
The outgoing dispatcher was in a hurry to finish his shift
ROOT CAUSE #2
Cause #3
PREVIOUS
WHY had the driver not received any information about the Temporary Speed Limit?
No safety notice for drivers was available when they took up duty
ROOT CAUSE #3
Cause #5
The OCC did not see fit to remind drivers of the speed limit
ROOT CAUSE #4
PREVIOUS
WHY did the driver misapply the speed limit?
He was distracted by his phone
He didn't understand the "driving-at-sight" rule
WHY?
ROOT CAUSE #5
He was tired and stressed
He had not turned off his personal phone
ROOT CAUSE #6
ROOT CAUSE #7
IN SUMMARY
Track unit not repaired BECAUSE spare parts not available Speed panel masked BECAUSE signal transmitted incorrectly by a dispatcher in a hurry to finish his shift Information poorly transmitted to driver BECAUSE no safety note or information from OCC Driving-at-sight not applied correctly BECAUSE practice poorly understood + driver fatigue, stress and distraction
PRÉCÉDENT