The smallest of things can cause thousands to be stranded
MAY 17, 2012
During the evening rush hour in the late summer of 2011 lightning struck near the Long Island Rail Road (LIRR), leaving thousands stranded. The LIRR was down, fully or in part, for almost six hours. In a system that was supposed to be protected from lightning incidents, one wonders how this could have happened.
Evidence points to a lightning strike near LIRR tracks creating a transient power surge that disabled the signal system that controls the train interlocking. While a lightning strike creating a power surge is normal, the impact of this particular strike was enormous yet hangs on a series of small errors during and after installation of the control system.
Let us review the Alltec Protection Pyramid: for comprehensive protection of a building or within a facility one must have stable grounding, adequate surge protection, and a well-designed and installed lightning protection system. Of course, if the grounding system is not stable or sufficient the proper function of the surge and lightning protection is in question. All electricity, including lightning, seeks the shortest and lowest resistance path to ground. If a grounding system is not adequate and designed to a single potential, then electricity will seek other more dangerous avenues of travel.
In the case of the LIRR lightning strike, the Office of the Mass Transit Authority (MTA) Inspector General (OIG) investigated and found a series of actions that created the environment for the damage to occur. Those actions were:
- The designer/provider of the signaling system that was damaged did not install the system
- LIRR employees installed the system and added a server the designer/provider of the system did not know about and did not design for
- While installing this server an incorrect connector was used, which was identified as the pathway the surge used to damage the system. This connector contained a built-in path to ground. In this application the connector should not have had a built-in path to ground.
- Surge protective devices that were supplied were not installed on the primary power circuits
So, an added piece of equipment thought to be innocuous, a connector that was incorrect, and missing but provided surge protectors led to the LIRR being down for almost six hours, stranding thousands on trains and in stations. The OIG has written an in-depth report on what happened and what can be done to prevent this in the future. Almost all of the responsibility is placed on human error and inadequate processes. To see the full report click here.