A. Rahmouni
Comparative review of Accelerating Moving Walkway Designs
Literature survey,
Report 2007.TEL.7122, Transport Engineering and Logistics.
Conventional Moving Walkways (AMWs) can be classified into two types: belt
systems and pallet systems. Belt systems make use of belts made of pure
rubber or rubber reinforced by fabric layer and steel wires. The belt can be
supported by a steel slider plate or rollers. Pallet systems can be
classified in two classes: systems that make use of pallets moving over
drums and system with pallets circulating in the horizontal plane. The first
class of systems can make use of pallets supported by two wheels or by four
wheels, the biggest advantages of the second class over the first are: the
smaller required pit depth and the possibilities to construct curved
sections.
There are four types of AMWs: multi-belt systems, roller systems,
sliding-pallet systems and parallelogram-pallet systems. Multi-belt systems
accelerate as a result of the small speed difference between the sequencing
belts. The movement of the handrail and treadway of this system is not
synchronized during acceleration. Roller systems make use of rollers to
accelerate. Acceleration is achieved as a result of a small speed difference
between the sequencing rollers. The movement of handrail and treadway of
this system is completely synchronized. Sliding-pallet systems make use of
sliding pallets. Passengers are accelerated as the distance between the
pallets becomes larger and decelerated as the distance becomes smaller. The
movement of handrail and treadway of this system is synchronized.
Parallelogram-pallet systems make use of parallelogram pallets. By guiding
the pallets in curved guide rails, the pallets move in such way that a side
velocity factor is created. The side velocity factor of a pallet becomes
larger until the pallet enters the high-speed zone. As a result, the
resultant velocity formed by the side velocity and forward velocity
increases. During deceleration the opposite process takes place. The
movement of the handrail and acceleration zones of this system is not
synchronized.
AMWs have the capability to accelerate, hence they are able to transport
people in a faster way than CMWs. However they consist of more components
and are therefore much more complicated. To achieve a continuous change in
speed, accelerating pallet systems make use of a folding drive chain, drive
axle or chains in combination with sprockets. The drive mechanism of their
handrail is also composed of a large number of components. CMWs make use of
a simple drive chain, and contain a simple handrail system. Accelerating
belt systems consist of multi belts installed in series. Therefore they
contain more components than conventional belt systems (make use of a single
belt). The level of complexity of the construction of accelerating and
Conventional belt systems is nearly the same, because they contain the same
type of components. The higher speed of accelerating systems does not effect
the theoretical and practical capacity. Thus, conventional and accelerating
systems with the same width and the same entrance speed have the same
capacity.
There are several factors which encourage or discourage the implementation
of an AMW. Encouraging factors are: reduction of the journey time of
passengers, increase of the service level and the ability to transport
people over larger walking distances. There are three discouraging factors.
Firstly, safety problems can occur at the beginning of the implementation
period, because people are not yet used to the system. Secondly, AMWs are
expensive, mainly because they are new. In general products are expensive
during the introduction stage because manufacturers want to earn back the
R&D costs made and because the products are traded in smaller
scales.
Third, AMWs that are used to bridge large distances could form some
flexibility barriers. People who want to cross over should walk large
distances around the system. Those who want to bridge shorter distances are
not able to make use of them.
The system characteristics of AMWs can be determined by analyzing the
properties of the construction. By assessing the characteristics, strengths
and weaknesses of each AMW can be made visible. The assessments made are
expressed in scores between one and four. The higher the score, the more
positive the assessment is. In table 1 the assessments of the
characteristics of AMWs expressed in scores are summarized.
Table 1: Comparative figure of system characteristics of AMWs
