This is material to supplement Warehouse
& Distribution Science, a textbook and a graduate course
taught at the Georgia Institute of Technology by John J.
BARTHOLDI, III and Steven T. HACKMAN. Everyone is welcome to use
the book and materials here for educational purposes, so long as
the copyrights remain intact. You will find more information and
technical details on these topics within the book.
Consolidated Freightways
Consolidated Freightway, also known as CF, went out of
business in 2002. They were a trucking company that competed in
the "less-than-truckload" (LTL) market, which means that typical
shipments are too small to fill the trailers. The challenge in
delivering such freight is to do it both quickly and efficiently.
Frieght can be delivered quickly by sending it directly to its
destination; but this would be terribly inefficient because most
trailers would be nearly empty.
The LTL carriers try to improve freight density by organizing
the flow into a hub and spoke network. Most shipments are carried
to large regional crossdocks that are "hubs" at which freight is
consolidated so that it joins other freight going in the same
direction. Thus a typical shipment will travel as follows: From
the origin to the local satellite terminal, where it is
transferred to a trailer along the spoke to the hub crossdock. It
will be transferred to another trailer, where it will join
freight traveling together to a destination hub, where it will be
tranferred to another trailer traveling along a spoke to the
destination terminal. Finally, it will be transferred to a local
truck for delivery to the destination.
The LTL carriers, such as Yellow Transport or Roadway or
American Freightways, that serve much of North America, typically
have 400-500 terminals and 20-30 hubs. Both satellite terminals
and hubs are crossdocks, but the hubs are where the highest
volumes of freight pass.
Within the crossdock the main concern is to move freight
quickly out of its arriving trailer and pack it tightly into its
departing trailer. It is important that each trailer be packed
full and tight. First, this prevents shifting of freight and
possible damage. Second, this increases utilization of the
trucks, trailers, and drivers. However, this is quite difficult
in LTL because, unlike the parcel delivery market, the freight is
of higly variable size and weight.
Click on any image to enlarge it.
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Like many LTL crossdocks, this one is a narrow rectangle
surrounded by doors at which trailers are parked to exchange
freight. |
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It may look like a truck but it is called a tractor.
Typically a tractor pulls two 28-foot long trailers, called
"pups". |
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Again this is typical of the industry: Freight has been
docked in the center of the floor, while forklift trucks drive
along the walls to carry freight to the appropriate departing
trailers. |
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To make the trip efficient, the trailer must be filled as
completely as possible. This one has been packed tightly so
far. |
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This is a badly-packed trailer. It looks like the loader was
having trouble fitting the freight together tightly and so
stacked some cargo in an unstable way. This freight could shift
in transit and cause damage.
Sometimes freight simply cannot be stacked with both high
density and stability. To a large degree the quality of packing
is determined by the cargo itself: Some things are hard to pack
because they do not fit well together. This is made worse by the
fact that the freight arrives as in a game of Tetris: The loader
can never tell what will arrive next. He can defer packing
freight by "docking" it temporarily, but there is limited space
to do this and, anyway, this requires an additional touch of the
cargo. Also, the freight cannot be held out long because it must
keep to shipping schedule.
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In fighting for business survival, CF made a business
decision which seemed reasonable at the time but which ultimately
hurt them. This was to get new business by lowering rates and
accepting some unusually hard-to-handle freight. You can see the
result in this trailer, where almost all the freight is loose and
so has to be handled individually, incurring larger labor
costs. |
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Another problem arose from the emphasis placed by CF on
filling trailers as completely as possible. To achieve tighter
packs, the workers de-palletized some freight because the smaller
pieces fit better. Unfortunately, this creates extra work, both
in the origin terminal (to de-palletize) and, especially, in the
destination terminal (to re-palletize). |
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This item takes up a huge amount of space for its weight --
and LTL pricing depends most strongly on weight. |
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This item is heavy and so should be loaded low; but it create
instabilities if anything was stacked atop it. It will probably
render the space above it unusable. |
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This shows some of the challenges facing LTL. Because of the
the North American Free Trade Act (NAFTA), the US, Canada, and
Mexico are exchanging trailers more freely. However, traffic laws
are not consistent. This US-based trailer did not have the
caution signs required in Mexico, so an enterprising driver
provided them. |
Copyright © John J. BARTHOLDI,
III. All Rights Reserved. This is material to supplement the
textbook Warehouse
& Distribution Science.
Last revised: 27 September 2003