Commuters trying to get to and from Penn Station are enduring a fourth day of delays, detours, and cancellations this morning following Monday's "minor" NJ Transit derailment in the station. Workers are still repairing the damaged tracks, necessitating the closing of eight out of 21 available tracks at Penn Station, thus impacting Amtrak, the LIRR, and NJ Transit. Yesterday MTA and NJ Transit officials publicly blamed Amtrak for failing to adequately maintain the tracks, which they own, and now NJ Governor Chris Christie is piling on.

In a letter to Amtrak CEO Anthony Coscia, Christie writes that "Amtrak’s apparent disregard for NJ Transit’s customers is entirely unacceptable to me." Pointing out that Monday's derailment was the second such incident in two weeks, Christie adds, "These incidents raise serious questions about the condition of the tracks and other assets on the NEC [Northeast Corridor]... The recurring derailments at PSNY [Penn Station] indicate Amtrak does not take its obligations seriously and has not applied NJ Transit's considerable payments to the proper maintenance of these assets..."

Read the whole thunderous letter here, but the point is that Christie says NJ Transit will stop paying Amtrak until "an independent examination" verifies that the tracks, signals, and other equipment is in a state-of-good-repair. Christie also says he's told New Jersey's Attorney General to consider legal action to recover the $62 million that NJ Transit has paid to Amtrak as part of their agreement for use of the tracks. (Speaking of money and infrastructure, it's worth remembering that in 2010, Christie pulled the plug on a project to build a new rail tunnel under the Hudson, which would have alleviated pressure on Penn Station.)

Amtrak has asked the Federal Railroad Administration to conduct "a thorough review of infrastructure at Penn Station to evaluate current conditions." Amtrak officials say they hope to have full rail service restored by Friday, and a spokesperson said the repairs are taking so long because the derailment caused "damage to one of the most complex interlockings on the Northeast Corridor, a location where two tunnel tracks diverge towards the 21 station tracks." (The Times made some neat graphics showing how many different train lines run through Penn Station.)

"Our plan is to work around the clock until we have the repairs done,” Amtrak COO Scot Naparstek told the Times yesterday. “We are forecasting at this point that we hope to be back at full capacity at the station by Friday.

It's still unclear what caused the derailment, but one official tells the Times the investigation is currently focusing on the condition of the tracks, not human error or mechanical problems. Railroad companies relying on Penn Station have seen a surge in ridership in recent years, increasing the strain on an old station with aging and limited infrastructure. An estimated 600,000 people and 1,300 trains pass through Penn Station on a daily basis during the week.

The LIRR cancelled 10 trains to Penn Station between 6 a.m. and 10 a.m. today, and NJ Transit is once again operating on a "holiday schedule," with some extra trains. Commuters are advised to expect delays; details here.