Another incident in an East River tunnel caused massive delays Monday for morning rush-hour riders on the Long Island Rail Road -- the sixth time a problem in or near the Amtrak-owned tunnels has caused disruptions in the past two months.
But officials said there appeared to be no common link.
"These latest incidents seem to have come in a cluster, no rhyme or reason; nothing causing this to happen," Amtrak spokesman Cliff Cole said. "There have been a few incidents over the last month or two, and we continue to work on upgrading and inspecting the tunnels."
The Metropolitan Transportation Authority, parent agency of the LIRR, later issued a statement acknowledging that "problems in the East River tunnels quickly lead to delays and cancellations. . . . Both railroads share the goal of keeping operations safe and reliable."
The disruption began Monday at about 7:15 a.m. when third-rail power and track damage in one of the four tunnels halted the westbound 6:15 a.m. from Huntington. The problem was fixed by 1 p.m.
The incident forced the cancellation or diversion of 15 trains and triggered systemwide westbound delays of up to one hour and eastbound delays of 30 minutes, a railroad spokesman said.
The train was stranded in tunnel number 4 and had to be towed by a diesel-powered "rescue train" about 8:15 a.m. It arrived at the Hunterspoint Avenue station in Queens about 8:55 a.m.
In addition to the June 17 derailment and Monday's disabled train, other recent problems affecting service on the LIRR include: July 12, when a train struck the electrified third rail at Penn at 5:07 p.m.; July 17, when a broken rail inside an East River tunnel at 4:30 p.m. caused delays; Aug. 5, when track repairs did not finish on time; and Aug. 6, when a "track defect" inside an East River tunnel just before 8 a.m. caused major disruptions to LIRR service.
Superstorm Sandy caused massive disruptions to the LIRR in October and November last year, but there was one severe disruption not attributed to the storm -- on Nov. 21, 2012, the day before Thanksgiving, when power and switching problems occurred in one of the tunnels.
There were three such incidents in the tunnels in 2011, all between February and May.