F
Fishrrman
Guest
As to what may have caused the derailment/collision…
I'm a retired engineman (Conrail/MN/Amtrak) -- worked on the New Haven line for 32 years. Retired in early 2012.
The derailment was in the vicinity of the [now-closed] Burr Road tower, under the I-95 overpass. There's a relatively gentle curve at that location. The eastbound train that derailed would have been turning "towards the right".
I belive tracks 2 and 4 there (tracks 1 and 3 are out-of-service for catenary and bridge construnction) had concrete ties installed several years' back.
I'm not sure how many others may have noticed, but concrete ties have significant problems in some locations due to moisture underneath. They literally begin to disintegrate (from the "bottom up") from the constant pounding of trains above. Unlike wooden ties -- which have some resliience and act as a "shock absorber" between the movement of the train above and the ballast below -- a concrete tie cannot absorb the forces from trains passing over them.
The result is that the ties will begin to grind away underneath, and the powdery residue will be visible on the track surface, as if someone had spilled a bag of cement all around the location.
Second factor: The type of insulated rail joints that are now being used to deliniate blocks. These are "pre-assembled" (I think some kind of adhesive is used to further strengthen them), and then spliced in at the required locations. The splices are then "welded in place" with the existing rails.
These insulated joints are very good when new -- almost undectable from the viewpoint of operating over them. But that's _when new_. As they age, they can work their way "loose", and the joint can begin to "fall down".
Now -- combine a location that has one of these aging insulated joints (perhaps on both rails) with concrete ties at a location where there is moisture underneath. Not only do you have the downward and lateral forces exerted by the train above, the point of wear is compounded by the bad joint, continually "pounded down".
At some point, the wear may be enough that something breaks under load.
If it were just "solid rail", a few ties might break. But under a bad joint, the joint itself might break, and now you have broken rail combined with ties that simply crumble under the stress. Thus -- the beginning of the derailment.
The fact that the location involves curvature, might explain why the eastbound on track 4 now fouled track 2 -- at the same moment that a westbound train was passing by.
From what I could see from the pictures available on the net, looks like the eastbound on 4 (that derailed) may have run into trouble just about where the "old limits" of Burr Road once were. The switches and signals are gone now, but the insulated joints still remain (this is where the second block west of CP255 begins).
This is only my guess:
The insulated joints of that location, on concrete ties, had worn down, resulting in heavy pounding of the ties below, which had begun to disintegrate. The forces of the passing train yesterday became "the straw that broke the camel's back" -- the joint broke apart, the train derailed and fouled track 2, after which the westbound struck it.
I could be wrong, but that's how I see it….As to what may have caused the derailment/collision…
I'm a retired engineman (Conrail/MN/Amtrak) -- worked on the New Haven line for 32 years. Retired in early 2012.
The derailment was in the vicinity of the [now-closed] Burr Road tower, under the I-95 overpass. There's a relatively gentle curve at that location. The eastbound train that derailed would have been turning "towards the right".
I belive tracks 2 and 4 there (tracks 1 and 3 are out-of-service for catenary and bridge construnction) had concrete ties installed several years' back.
I'm not sure how many others may have noticed, but concrete ties have significant problems in some locations due to moisture underneath. They literally begin to disintegrate (from the "bottom up") from the constant pounding of trains above. Unlike wooden ties -- which have some resliience and act as a "shock absorber" between the movement of the train above and the ballast below -- a concrete tie cannot absorb the forces from trains passing over them.
The result is that the ties will begin to grind away underneath, and the powdery residue will be visible on the track surface, as if someone had spilled a bag of cement all around the location.
Second factor: The type of insulated rail joints that are now being used to deliniate blocks. These are "pre-assembled" (I think some kind of adhesive is used to further strengthen them), and then spliced in at the required locations. The splices are then "welded in place" with the existing rails.
These insulated joints are very good when new -- almost undectable from the viewpoint of operating over them. But that's _when new_. As they age, they can work their way "loose", and the joint can begin to "fall down".
Now -- combine a location that has one of these aging insulated joints (perhaps on both rails) with concrete ties at a location where there is moisture underneath. Not only do you have the downward and lateral forces exerted by the train above, the point of wear is compounded by the bad joint, continually "pounded down".
At some point, the wear may be enough that something breaks under load.
If it were just "solid rail", a few ties might break. But under a bad joint, the joint itself might break, and now you have broken rail combined with ties that simply crumble under the stress. Thus -- the beginning of the derailment.
The fact that the location involves curvature, might explain why the eastbound on track 4 now fouled track 2 -- at the same moment that a westbound train was passing by.
From what I could see from the pictures available on the net, looks like the eastbound on 4 (that derailed) may have run into trouble just about where the "old limits" of Burr Road once were. The switches and signals are gone now, but the insulated joints still remain (this is where the second block west of CP255 begins).
This is only my guess:
The insulated joints of that location, on concrete ties, had worn down, resulting in heavy pounding of the ties below, which had begun to disintegrate. The forces of the passing train yesterday became "the straw that broke the camel's back" -- the joint broke apart, the train derailed and fouled track 2, after which the westbound struck it.
I could be wrong, but that's how I see it….As to what may have caused the derailment/collision…
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