Double stack trains

[Anonymous]

How is the top container secured to the bottom container in a double stack configuration? Also, How is the container secured to the trailer frame-is some type of pin/locking mechansim used, or is it just the weight of the container that secures it?

[Anonymous]

Most often it is secured with a pin and wedge the weight of the top and bottom containers hodl them in the well car. Rodney Beck switchman BNSF

[Anonymous]

Then trailers are constructed with "female" receptors, in which the pin is inserted? If so, where are they located on the trailer-end,sides etc..Where/how is the wedge used?

[mudchicken]

The "pin" Rodney is referring to is called an IBC (Inter Box Connector)...It is made of cast aluminum with a machined steel pin going up through it. It is about the size of a football and is a double ended male connection. Weighs about 22 pounds.

I.E. ... Take a football. Stand it on end. Divide the football into thirds. (Top, middle and bottom with the middle part equal to about twice the size of the top or bottom) Drill a hole through the top of the football about 2 inches in diameter and drop a same sized pin through the hole. Fix the top and bottom pins to the steel pin.

Before putting the whole assembly together, do a little machining to the three parts of the football. (1)To the ends of the football, plane-off/grind off about 1/4 of the round side of the end section (Looking top down, you get a rectangle with curved short sides with the pin hole in the center of the rectangle)...Round all the edges...This is the "male" connector. (2) To the middle portion of the football, cut a 3/4" slot through opposite quarters of the round section...this will accept a little 1/2"steel dowel through the slot and a 1/2" pilot hole drilled through the 2 inch pin mentioned earlier.

The 1/2 " dowel is the handle that opens or closes the IBC to hold the two containers together.

If you see an odd looking hunk of steel lying in the ballast somewhere, it may be an IBC that fell off a car coming out of a TOFC/COFC yard. Some yardman's forgetfulness in misplacing an IBC just cost the railroad $50.00 for a now "lost" IBC that fell off a railcar somewhere out on line.

Connecting the bottom container to the car has different possibilities. It could be sitting on a simple vertical pin held down by gravity, it could be sitting on a modified IBC with one end somehow fixed to the car or more likely it is fixed in place with a simple pin through the SIDE (Take a close look at the "cube" female connector on the container (also called a "sea can"), it has oval holes in the top, bottom and sides ...The folks in the intermodal yards know the type of connection by the type of car...

The highway trailers use a similar type of IBC integrated into the trailer frame. Many trailers have a telescoping frame to adjust to the different sizes of sea-cans (20'-40'-50'-54' and so on)...at the docks, dockworkers and draymen use a "bomber chassis" to put the container on (no pin connection, just gravity) while moving the chassis around at the dock for storage or transfer to another mode of transportation. The telescoping trailers are stood on end in special racks when not in use to conserve storage space.

[Anonymous]

Hold the patent? Nice job.

[mudchicken]

IBC's make for effective doorstops/ conversation pieces too! (Found mine on a recently abandoned piece of railroad)

[Anonymous]

Some times when they run short of the IBC pins they can use a pin that is about 2" in diameter and about lets say 3-4" long that has been machined to accept a wedge. It is some what cheaper than the IBC and can accompli***he same results. Rodney

[DTomajko]

Jack,I work in an intermodal yard and an IBC,(we refer to them as bullets),weigh about 10 to 15 pounds and are made of galvinized or zinc-coated steel.The top and bottom are one-piece of cast steel and is shaped like the letter "I".The top is pointed to make it easier to place the top box on and the bottom is flat with small protruding ears on the end corners.A handle protrudes from the shaft in the middle at 45 degrees to the top/bottom pieces.A bolt together 2-piece casting surrounds the center shaft and seperates the top/bottom sections with a slot for the handle to turn 90 degrees.The center 2-piece casting is formed to loosely fit into the oval holes in the top and bottom of ALL containers,(except one common type),and extends to the sides of the opening so that the two boxes are seperated by about an inch and hold the containers from sliding sideways or forwards/backwards.When the handle turned fully open,the ears on the bottom piece hold the IBC in the lower box,so when the top is lifted the bullet stays behind.Turning the handle 5 degrees allows removing the IBC by the yard groundman.By turning the handle the full 90 degrees of travel,the two containers are securely locked together.It is a suspendable/fireable offense to allow stacked containers to leave the terminal with theIBC's unlocked.I have seen examples of empty boxes blowing off the top position when not locked in areas of high winds.As for the bottom container,the floor of the well has cone shaped pieces welded to hold a 40 foot container with extra wedges front and rear to keep it from sliding forwards/backwards.All well cars I have seen have their floors laid out in this fashion and longer boxes have stacking posts and cutouts to accommadate the floor bullets and wedges.On cars made to accept 110" containers in the bottom well,there are flip-over castings to secure a 96" box in the bottom position.On a 40' or larger container chassis,there are wedge-shaped twistlocks that mate with the same sized holes as the stacking posts and are locked with a 90 degree turn of a handle.The front locks are usually 1.5" round steel that slides in to matching holes in the front of the box.On 20" chassis,there is twistlocks on all 4 corners.By the way,very few chassis are extendable,most are solid 40',48',or 53'.Extendables are usually 40' to 45';40',45',48',or 48'to 53'.All containers,(except 20'),have stacking posts and holes located at the 40' location.The only excemption to this rule is older JBHunt 53' boxes that have no holes in the top to stack another box on.The newest Hunt 53's are Duraplate models and now have holes.Also,all containers bigger than 40' have matching holes in the front and rear to mate to the appropriate chassis.On the older Gunderson stack cars with the high ends,there aren't any IBC's used since the ends restrain the top containers,(no climbing on these cars for the groundman!).I hope I was a little bit of help to you. DT,Pa.

[Anonymous]

Thanx, DT, for yr very informative post. Could you tell me, in the case of 20' containers loaded on a double-stack car, is it correct that they are loaded only on the bottom? Meaning that it is ok to have a 40' or longer box on top of two 20-footers, but that two twenties would never be loaded atop a 40-foot or longer container. Is this correct?

Thanx for yr time if you can answer this--it is always great to get answers from working railroaders who know their stuff! Sincerely, jwm

[DTomajko]

You are absolutely correct,20 foot containers are always on the bottom of a stack and always in pairs.Even if nothing is on top,there must always be two 20's in the well to keep both from moving around.Also take note that the side of the wells are marked as to whether they accept 20' boxes.Most multi-well cars only take 20's in the 2 end wells and not in the intermediate wells.In order to load a single 20 footer,you would need a TTAX All-Purpose car,(only on the end platforms again),or a pedestal equipped or container only flatcar.By the way,most if not all intermodal terminals are operated for the railroads by subcontractors,such as my employer.The railroad provides yardmasters,car inspectors and repairmen,a shifter,and usually the gate clerks and the packers.We handle all equipment on or off the train,trailer or packer repair,and lot maintenence,(snow removal,etc.).I hope this has been of some help. DT,Pa.