For want of an isolating ground, a railroad was shutdown

[Danny Burstein]

[from the IG report looking into a Long Island RR
    (NYC suburban commuter line) failure last year]

At approximately 4:30 p.m. on 29 Sep 2011, the beginning of the evening
rush, lightning struck near Long Island Rail Road (LIRR) tracks, creating a
power surge that disabled the signal system controlling the train
interlocking just west of Jamaica Station

Approximately three and a half hours after the strike, in an attempt to
repair a computer server believed to have been damaged by the power surge, a
LIRR employee erroneously disabled the separate signaling system controlling
the train interlocking just east of Jamaica Station. At that point, all
service was suspended.

 * So, how did lightning get through the various safeguards?

The report continues:

Specifically, OIG found that:

In accordance with its contract, ASTS designed the new signaling system for
the Jamaica Interlocking but LIRR employees installed it.  During the
installation, LIRR added a piece of computer equipment called a "serial
server", which was not part of the ASTS design.  This server allows LIRR to
remotely monitor various pieces of the equipment.

In the course of attaching the server to the new signaling equipment, a LIRR
employee used one incorrect connector.  ASTS, LIRR, and Systra all agree
that this connector created the pathway by which the power surge generated
by the lightning damaged the signal system and brought it down.

rest: http://mtaig.state.ny.us/assets/pdf/12-01.pdf

------------------------------