What would cause a double stack to lean?

[steve-in-kville]

Seen  a few container trains over the weekend. One double stack, in the middle, was leaning pretty hard. What would cause this? Was it not latched right?

[Overmod]

steve-in-kville

Seen  a few container trains over the weekend. One double stack, in the middle, was leaning pretty hard. What would cause this? Was it not latched right?

Most likely shifted load in the box on the top.  The same idea as shifted load in a trailer.  Might be dunnage failure or problem within the cargo such as free-surface effect from released liquid running under pallets; might have happened during handling or on a ship except I can't imagine anybody letting such a thing out of the origin facility, let alone any rollthrough inspection at any subsequent point on the railroad...  

Spring failure and some types of side-bearing failure, as you can guess, could cause a double-stack car to lean.  But in the middle of an articulated set I'd think it would be likely that both stacks on either 'side' of the affected truck would be leaning.

It's certainly an emergency condition to be promptly reported if you observe it.

[SD70Dude]

Lots of them lean a bit, but it's usually not noticeable unless you're right next to the cars.

If it really catches your eye like this it should be reported, most likely is a shifted load as Overmod stated.  It's not uncommon for such a car to be set out and a crane called to unload the offending box(es). 

[bratkinson]

Although the computer at intermodal terminals prevents heavier containers to be stacked atop lighter ones (there IS some allowable difference), there's nothing that physically prevents it from happening.  Arriving containers on a train frequently don't exactly match where the computer shows them located.  Usually they're within a bucket or two of where the computer shows.  But I've also witnessed them more than 5 cars away from where shown.

As mentioned above, the lean is most likely caused by a shifted load that wasn't properly blocked and braced.  I know CSX has specific instructions for loading and blocking and bracing containers...I was asked to mail them to a shipper that repeatedly failed to properly load their containers and I refused them at the gate.  Typically, large inflatable 'bags' and/or 2x4 blocking and bracing is used with 2x4s frequently nailed to the oak floor to prevent longitudinal sliding.

While at CSX Intermodal, I received a number of emails from yards between Chicago and West Springfield where I worked indicating that doors were open on one or more containers headed our way.  While I never got any regarding a shifted load, I'm sure it happens.  Most often, however, the shifted load would not appear big-time shifted while unloading and putting on a chassis.  I DID, however, have a number of drivers come to the gate with or without their load and tell us they're refusing to take it as it is leaning more than just a little.  In those situations, we (CSX) had to contact the shipper to get permission to open the container and inspect why it is leaning.  Once inspected, it usually required that we contact the shipper again to arrange for transloading to another container by a bonded company that would properly block and brace the transferred load.  We only had one such authorized company in the area at the time and provided their name and phone number to the shipper so they could make arrangements.  When done, we had a special action in the computer to 'transfer the load' to another container to keep the billing accurate, etc.

On the other hand, if the container is really leaning badly, it's likely a high & wide detector would catch it and the train inspected.  If needed, it could be set off at a siding somewhere, but there's no highway-compatible cranes that I'm aware of that can pick up a container using twist-locks at the top of each lifting post.  And if they DID succeed in getting it off, they'd be 'on their own' to contact the shipper, etc, then putting it back on the train.  In other words, that would be extrememly unlikely to ever happen except in case of a derailment.

 

[jeffhergert]

I've heard of a well car floor starting to give way causing the containers to lean.

Jeff

[Overmod]

bratkinson

there's no highway-compatible cranes that I'm aware of that can pick up a container using twist-locks at the top of each lifting post.  And if they DID succeed in getting it off, they'd be 'on their own' to contact the shipper, etc, then putting it back on the train. 

I think there is no particular difficulty adapting a spreader to something like one of the large Grove off-road-capable cranes -- I actually started designing one at one point, when I was interested in precast concrete house fabrication and had the opportunity to pick up one of what I recall was a six-axle variant very cheap in good condition (I believe it was used in oilfield logistics somewhere, and this was in the why-is-a-pigeon-different-from-a-Texan years).  The catch, of course, is that the crane will never be near the point where it would be needed, and the special spreader arrangement would require training to use safely, so the cost would be through the roof, and some side-fork alternative more likely.

I always assumed that the container would be lifted and held, and the train moved to position an empty well under the lift, or that the crane would swing it to a blocked temporary foundation for either transloading or stripping and (re)stuffing in place.  I had a brief vision of an offroad crane actually carrying a container to where it could be put on a skeleton truck chassis for road retrieval ... but no.