though many commonalties exist between such a system and PCP.
The greatest advantage of this system is it can carry large size cargoes—
including standard containers. The drawback of the system is
high cost.
A study is taking place currently in Florida for transporting
phosphate by using PCP (8). The PCP is to be driven by linear
synchronous motors (LSM) instead of linear induction motors
(LIM). LSM may have slightly higher efficiency than LIM, but it
is difficult to control because the capsule speed and the motor
speed must be synchronized. Furthermore, synchronous motors do
not self-start. The motor has zero thrust when capsules are in standstill.
The rotor (capsules in this case) must be brought to synchronous
speed by some other means (a starter) before the LSM can start
to work.
A third study is being conducted at Texas Transportation Institute
(TTI). In the TEA-21 legislation, TTI was authorized (and funded
with $1.125 million) to conduct a feasibility study of using PCP to
transport freight in Texas in order to reduce truck traffic (9). The
scope of the study does not include research to improve the current
system.
Finally, in 1998, the Mid-America Transportation Center, in
collaboration with the Sumitomo Metal Industries, Ltd. in Japan,
sponsored a PCP research project at the Capsule Pipeline Research
Center (CPRC), University of Missouri-Columbia. The project is
focused on studying the use of LIM for PCP. The pertinent electromagnetic
and fluid mechanics equations have been derived (10, 11).
Currently, preparation is underway to test a special LIM for PCP
donated by Force Engineering, Inc. in England (see Figure 5). The
test data will be used to verify the equations derived so that these
equations can be used with confidence for designing future PCP
systems powered by LIMs.
Other much needed research before the improved PCP can be
developed and used smoothly in commercial applications includes
a study to construct PCPs along highways easement, testing the
use of modern bar code scanning systems to detect, identify, and
control PCPs, designing a new system for efficient off-line loading/
unloading of capsules, and investigation of the economics
and market of the new PCP system.