The Long Island Rail Road's upper management brought in an outside consultant to find the cause of this derailment. Some viewed this action as a confirmation of the president's contempt for her own employees, others felt the last qualified investigator on the property retired years ago.
The finding was called a "classic low speed derailment". The train had four dead cars in the middle causing unusual slack and buff action. Contributing further was the M-7's feature which increases propulsion power of the remaining cars when some of the consist is dead.
The engineer, feeling a power loss in an area with long gaps notches the controller for more power. This caused excessive slack and buff action which caused the train to either pick or walk off the switch.
Contributing to the cause was excessive Sandite in the switch points, and a lack of lubrication as the flange greasers (grease pots) were foolishly and dangerously disabled in compliance with President William's orders due to system wide slip slide conditions.
The M-7 equipment also has notoriously tight trucks which, as A-23 can tell you, can also have contributed to the derailment.
I suppose now President Williams will have to find another consultant to tell her how this can be avoided in the future.
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The Long Island Tool
"... overzealously discharges his duties;
...a "tool" of the administration"