ryanov wrote:I wonder if there's any way those two things could be related? I went into NY on Saturday afternoon and they were using only the north tube, and maintenance crews were working right by Tonelle Ave on the south tube. Seems a little coincidental.
While I am not privy to the investigation, it is unlikely to be coincidental. In most places the catenary and contact wires for both tracks is supported by the same structure. That is, there are two masts on each side of the two tracks with cross span wires that support the catenary and the contact wire. Sometimes instead of cross span wires there are K-frames (K laying on its flat side) between the two masts. Cross span wires seem to be the dominant way of installation in Europe, but in the US the K-frames are preferred in spite of their higher cost. When cross span wires are used damaging the wiring system on one of the tracks pretty much guarantees damaging the wiring system on the other track too. That is because the pantograph of a train in motion will break all the cross span wires for quite a distance. With a K-frame, typically the pantograph gets broken while the K-frame survives (and so does the wiring on the other track). Most of the old work on the NEC is with cross span wires and I believe the area next to the entrance of the tunnels also uses them.
With that in mind, I will now speculate on what happened. The information released so far is consistent with the train going into Penn in the south tube damaging the cross wires (or the K frame) supporting the contact wires for both tracks just before the tunnel entrance. The pantographs are spring loaded, so once the resistance of the contact wire is gone they shoot up to the maximum height possible. Entering the tunnel at that maximum extension is guaranteed to break of the pantograph. On an Arrow set, that actually means breaking multiple pantographs. With that in mind it is not surprising that some piece actually went through the roof of a car. I personally have not been able to identify from the images published in the media where the piece that penetrated the roof came from. On the images it seems to be L angle piece of steel, but most pantographs have round steel for their arms. When the cross wires( or the K-frame) were damaged, the contact wire in the South Tube shorted and the over-current protection devices turned off the power. In a situation like this the same is very likely to happen to the contact wire in the North Tube because at that point it was likely sagging. That is why the west bound train lost power -- the over current device for that track tripped too. The dispatchers probably restored power in the North Tube immediately as per protocol not knowing what had happened (or the extent of it). The westbound train was able to continue, but once it exited the North Tube it hit the already damaged cross wires (or K-frame), insulators and other accessory catenary structures that were not properly positioned any more). At that point the westbound train might have also broken its pantograph or at the very least caused additional damage to the contact wire on the westbound track in the vicinity of the tunnel entrance. The need for Amtrak to remove the wires before a diesel could bring the train to Secaucus is consistent with such additional damage.
The one thing that I will not venture to speculate on is whether the initial cause was defect on the train that was going into Penn or by defect on the catenary/contact wiring. However, none of it is likely directly related to the Sandy damage to the tunnels. Most likely it is lack of maintenance on the train (and its pantographs) or lack of maintenance on the catenary/contact wiring.