As I watched a double stack train with many JB Hunt containers pass through Temple, TX today, I got to wondering. Who came up with the idea? Was it the railroads or the truckers or both together?
I don’t know the absolute origin but in the mid 1980’s Santa Fe President Mike Haverty took Mr. J B Hunt on a business car trip from Chicago to LA behind a Santa Fe fast stack train, perhaps the Super C. As a result Santa Fe got their business along routes which interfaced with its Railway.
You can thank Southern Pacific, SeaLand, and American Car Foundary for pioneering the concept. Far as I know APL and SeaLand were the first customers to use the service for land bridge traffic.
I never understood why the fractional improvement in containers per siding-constrained train length added up to an advantage over a number of disadvantages.
For one, the number of containers is not doubled because there are gaps between container wells required for the trucks. I have also seen many a stack train where a goodly number of the cars are only loaded with a single stack of container. Two, it must have cost capital up front to insure that these excess height cars could fit under bridges on the routes involved, and there must be places these cars cannot go. Three, there must be a big boost in aerodynamic drag to have the loaded cars that tall and to have the large gaps between the containers.
Four, I can understand that inbound ocean containers are served by a yard with gantry cranes, but the receiving intermodal terminals need either gantry cranes or Piggy Packers with a high reach. There are side-transfer options for single-level containers, which could reduce the cost of a terminal, allow for more local terminals and reduce the distance and hence cost of drayage (trucking) to the final distination.
Five, with respect to the use of articulated well cars, the intermediate trucks are probably at weight/axle load limits – evidence of this is the use of a larger wheel diameter that tolerates higher loading. In using articulated cars, the use of “3-packs” may have to do with the articulated trucks all being shared between one end car and one intermediate car that reduces the axles loading somewhat. Limiting the number of articulated cars as does the use of double-trucked well cars on 53-foot trailers also increases gaps and air resistance, which is a major contributor to fuel consumption of fast intermodal trains.
The whole enterprise has a “feel” of optimizing one metric – the number of loads per train – without looking at all costs and the “big picture” of an intermodal train as part of a larger transportatio
A couple of years back, there was a BNSF video that showed a stack train in the Abo Canyon area { at the time , the major construction project was in the process of accomplishment). The engine in that video was equipped with an annometer attached to the cab area. To what Paul Milenkovic noted,it seemed pretty obvious BNSF was gathering some information in regards to winds and areodynamics(?). So there must be some private data in their engineering department(?).
Then of course, because of TRAINS coverage, we knew there was the UPRR’s ‘AirFoiler’ experiment, which apparently, came a cropper when it was damaged under a bridge in Wisconsin. Which apparently, ended their experimentation(?).
Watching BNSF stack trains going thru this area, they seem to use plenty of power to move them (normally, 4 or 5 GE’s on the head end). Solid trains of 53’ containers on a train (5/6k ft?). Spacing on one of them is pretty close beween containers.
It is the solid Import/Export containers ( 40 to 45 ft) where there seems to be a gap between stacks of something on the order of 10 to 12’ (?), The big stacker’s with mid train DPU’s will have 2 or 3 engies on headend; Mid train DPUs will be 1 or 2 units and on the rear similarly 1 or 2 in DPU. Plenty of HP does not seem to be a problem for BNSF?
Another thing to think about is what the other option was when double stacks were first developed. There was still a lot of TOFC at that time. The wind resistance on those was terrible.
In the 1970’s Santa Fe’s Engineering and Computer Programmers developed a train simulator program which, among other factors, analyzed wind resistence. It further determined which locations along what we now call the Southern Transcon were most vulnerable under 'normal’conditions. Thus the power could be added or reduced on certain operating districts, of course also dependent on other factors. No doubt that has all been refined through the years and helps to explain the success BNSF has along this ‘transcon’.
Aside from the 1970’s fuel crisis. Did any of this data help lead to the development of the fuel foiler concept?
[quote user=“Paul Milenkovic”]
I never understood why the fractional improvement in containers per siding-constrained train length added up to an advantage over a number of disadvantages.
For one, the number of containers is not doubled because there are gaps between container wells required for the trucks. I have also seen many a stack train where a goodly number of the cars are only loaded with a single stack of container. Two, it must have cost capital up front to insure that these excess height cars could fit under bridges on the routes involved, and there must be places these cars cannot go. Three, there must be a big boost in aerodynamic drag to have the loaded cars that tall and to have the large gaps between the containers.
Four, I can understand that inbound ocean containers are served by a yard with gantry cranes, but the receiving intermodal terminals need either gantry cranes or Piggy Packers with a high reach. There are side-transfer options for single-level containers, which could reduce the cost of a terminal, allow for more local terminals and reduce the distance and hence cost of drayage (trucking) to the final distination.
Five, with respect to the use of articulated well cars, the intermediate trucks are probably at weight/axle load limits – evidence of this is the use of a larger wheel diameter that tolerates higher loading. In using articulated cars, the use of “3-packs” may have to do with the articulated trucks all being shared between one end car and one intermediate car that reduces the axles loading somewhat. Limiting the number of articulated cars as does the use of double-trucked well cars on 53-foot trailers also increases gaps and air resistance, which is a major contributor to fuel consumption of fast intermodal trains.
The whole enterprise has a “feel” of optimizing one metric – the number of loads per train – without looking at all costs and the “big picture” of an i
The early stack trains were the brainchild of American Presidents Line. (APL). They got the SP and later the UP interested in runnind double stack trains of marine containers. Stack trains have really good load/tare ratio, conserve terminal pad track space, and allow trains to fit into more passing sidings.
RRs liked the operational cost savings and being able to avoid add pad track space to terminals, so they pushed all the intermodal customers to start stacking. Some of the premium customers pushed back - their operations were more flexible with TOFC equipment (UPS, LTL carriers, etc.)
Now, we have all steamship and a big chunk of truckload traffic moving in stacks with a relatively small amount of premium traffic and niche truckload stuff going TOFC.
When CSX opened its ramp at Chambersburg, PA about a decade ago - the track facilities were constructed with 13K feet of track for rail cars to service the facility. When the ramp was opened there were a number of locations, both on the Main Tracks from Cumberland to Cherry Run as well as on the Lurgan Sub to Chambersburg that caused loadings to be clearance restricted to single stacks. Plans were in progress to make the route available to double stacks. While the route was only being used with single stacks Chambersburg frequently had more than the alloted 13K feet of traffic and was routinely operating two trains in each direction, daily.
Once the clearance modifications were completed to allow double stacks - one train daily that was 9K feet or less easily handled to business.
If you can beg, borrow, or scan one, get a copy of the November 2011 TRAINS magazine!
EVERYTHING you EVER wanted to know about the history of double stack trains is in there!
In particular, an article by one of the key people in development of double stack - Dave DeBoer - wrote a significant article show the who, what, when and how it all came together in the 1970s and 1980s. The entire issue is a bonanza of intermodal must-read information!
That’s the same story I heard when working at American Steel Foundries in 1991. ASF’s development of the articulated connector was a factor in making it work and made ASF lots of money. I can’t recall the name of the driving force at APL, but he was well known and respected in the industry. The AAR was incredibly slow to allow the double stack cars in interchange service so as I heard the RR’s operated them by inter-line agreement as AAR dragged it’s feet in approving the car design.
What I saw during my time on the freight car side of the RR industry was that the AAR would delay and delay issuing approval of new design components until a second supplier had developed a competing device, at which point the rail equipment buyers could get the suppliers bidding against each other to lower the price. It made it unattractive to develop new and better devices, rather only cheaper versions of the same old thing, which is why we are still using the 3 piece truck in spite of it’s well known deficiencies.
Dave
Summary of APL initiating stack train service. Pay attention to the second part as it explains the imbalance of traffic flows. Also later in the summary how stack trains have reduced cost.
The linked article claims reduced fuel consumption on account of reduced tare weight relative to what – 89’ COFC/TOFC cars taking a pair of 40’ boxes at the time? Whether the tare weight reduction is that great over an articulated spine car needs to be considered.
I argued that a double stack, because of its height and because of large gaps between containers, must have an aerodynamic penalty over single-level. I get that in most freight operations, weight, especially in overcoming grades is the dominant factor in fuel consumption. But intermodals are the fastest freight trains out there, and the aerodynamic fuel penalty of piggyback is regarded as substantial. I would be suprised if double stack is more fuel efficient than piggyback given the height and the gaps.
Obviously, the “know nothing idiots” working for the railroads disagree.
[quote user=“Backshop”]
Paul Milenkovic
SD60MAC9500
Summary of APL initiating stack train service. Pay attention to the second part as it explains the imbalance of traffic flows. Also later in the summary how stack trains have reduced cost.
The linked article claims reduced fuel consumption on account of reduced tare weight relative to what – 89’ COFC/TOFC cars taking a pair of 40’ boxes at the time? Whether the tare weight reduction is that great over an articulated spine car needs to be considered.
I argued that a double stack, because of its height and because of large gaps between containers, must have an aerodynamic penalty over single-level. I get that in most freight operations, weight, especially in overcoming grades is the dominant factor in fuel consumption. But intermodals are the fastest freight trains out there, and the aerodynamic fuel penalty of piggyback is regarded as substantial. I would be suprised if double stack is more fuel efficient than piggyback given the height and the gaps.
Obviously, the "know nothing idio
It should not be a surprise that the main benefit of doublestacking was to cram more boxes into the same length of train.
As for tare weight, a quick look at Greenbrier’s website shows that their current 89’ flatcar design weights 83,000 lbs, while their single 53’ well car weighs 55,000 lbs. A 3 or 5-pack’s tare weight per carbody would be a few tons less, due to having fewer trucks. Ditto for 40’ wells due to their shorter length.
Air resistance can be minimized by loading a train with as many doublestacked cars together as possible, or but putting a 53’ container on top of a 40’ container to minimize the gap. That’s not always possible, but every little bit helps.
I would think that the gap under the trailer creates a significant amount of air resistance friction. Placing trailers in well cars could help eliminate this, though perhaps the higher tare weight of the well car over the spine car would outweigh this benefit. CN used to do this on intermodal trains in eastern Canada, so they would fit through the old St. Clair River tunnel.
These benefits of doublestacking were both apparent and well known in the industry before Hunter Harrison ever came to Canadian National.
There’s a fairly hard limit on reducing tare weight in spine cars that don’t operate in dedicated relatively short trains, for reasons demonstrated or worked out by the time of the Portager experiments. You can’t get much lighter than the FuelFoiler 10packs with load’bearing either on the trailer axles (an iffy thing for a variety of reasons) or on the kangaroo pockets, and you’re into the tare-weight range of the lighter well cars (which can use bridge-type and hollow-box construction in the well sidefames and are aggressively lightened almost to the point of fragility in well-bottom material, walkway and platform structure, and equipment mounting).
Part of the revolution comes with twistlock corner-casting economies, too. Van trailers in typical TOFC have to be reinforced to be lifted by these, and it is just as much mandatory to lift a van off an ‘advanced’ spine car as to lift it out of an articulated well suitable for other traffic. Once you have the specialized handling equipment for ISO containers sufficiently built out with, say, sea-land bridge operations, and suitable third-party and aftermarket support assured, a great deal of what can only be achieved ‘cheaply’ in more proprietary or operationally-limited approaches … including my beloved lateral sideloading means for containers … become financially less preferable.
Note that a great deal of facile and sometimes thoroughly thought-out ingenuity has been directed at the issue of aerodynamic gaps between containers in articulated sets. One example was supports on adjacent cars that would take a sort of lightweight high-cube 20’ unit, which would circulate in a kind of parallel traffic with marine-container stacks, articulated over two coupled car-ends of well equipment. In practice this was about as valuable as the expensive Ericsson (I think it might have been Sony-Ericsson doing the actual “thinking”) and Lucent research into 'ut
This is one of those “Where do I start and where do I go threads.” It deals with the very real cost savings of double stack and, simultaneously, with the cost savings as shown by cost accounting. They are in no way the same thing. It seems most people think cost accounting is a very cut and dried procedure that produces an accurate number that you can put in the bank. It ain’t no such thing.
In reality there are fixed and joint cost that tend to get allocated as in: “There are seven switch engines in Louisville and somebody’s got to pay for them.” The cost accounting was allocating costs to intermodal that intermodal didn’t use. But, hey, somebody’s got to “Pay for them.” By allocating cost to a service that didn’t actually incur the cost the accounting was running the railroad out of business.
We were price takers, not price setters. What we could charge was determined by truck competition. If the allocated cost was above what we could charge we lost the business. The allocated cost had nothing to do with the actual cost, but such accounting would show a loss on business that actually sent money to the railroad’s bottom line. If we backed out of such business, due to “loosing money” the allocation would go to other rail business and increase their accounting cost. Then that business would also be lost due to price and the cycle would repeat. That’s a formula for going out of business.
Cost accounting is a can of worms in a lot of businesses. It’s particularly wormy in railroading due to the large fixed and joint costs which cannot be accurately assigned. I never saw any railroad cost accounting that included “wind resistance.” It all related back to tonnage. As in, just relate the line haul cost back to the tonnage moved by dividing total costs by tons moved. Tis garbage.
Remembe