System Operation
When the computer advises Tranz Link that the wagon loading
has been completed, it produces a waybill for that consignment.
The system then combines its files of scheduled trains and timings
to find the best route for the movement. Having allocated the
particular consignment to a particular train, the computer is
able to provide train lists showing loads, wagons and their
destinations, the list are then passed to yard staff. With the
train made up, a works order is passed to the crew. |
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The Eureka 811 AVI Tag
Automatic Vehicle Identification using the Eureka 811 High
Speed Tagging system has been installed at the entrances and
the exits of all the principle yards, Dunedin, Middleton,
Picton, Hastings, Mt. Maunganui, New Plymouth and Auckland.
10,000 811 High Speed Tags were fitted to the wagons at a
rate of 700 a week. Each of the 811 tags can be read at up
to 110km/h however the speed over the electronic weighbridges,
supplied by Railweight, is limited to 70km/h, well within
the capability of the 811 tagging system.
The 811 Tag used at Tranz Link is of the Active read/write
type, this means that data can be received from the tag as
well as transmitted to the tag. The tag can contain up to
115 Alpha Numeric characters of Data at any one time. The
speed at which each of these tags can be read is dependent
on the amount of date being transmitted. In tests the 811
tag.
The system operates at low frequency (132kHz/66kHz) to communicate
with the transponders. The frequency used can penetrate all
non-conducting materials, and will operate around metals.
This meant that for Tranz Rail the 811 tags would operate
through brake dust, oil, ballast, dirt, water and ice. As
well as all common building materials.
The use of low frequencies allowed flexible antenna design
with the ability to precisely control the antenna field, allowing
closely positioned transponders to be read at high speed.
Ruggedised antennas are installed on concrete plinths at the
track side to read both the container and wagon tags. Many
of the antennas are used in multitrack situations, because
of the characteristics of the 811 low frequency system, all
possibilities of tag cross talk i.e. an antenna reading the
wrong tag, have been eliminated.
Conclusion
This 811 system is easy to install and provides high
speed performance together with an ability to collect a wide
variety of Data, which gives this system great flexibility
for identification applications.
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