Au t o m a t e d Pe o p l e M ov e r
System "Crystal Mover" forSingapore's LTA
HIROYUKI MOCHIDOME
MASAHISA MASUKAWAYASUYUKI SUZUKI
MAKOTO KASHIWA
SHINICHI SADAMITSU
HIROYUKI KOUNO

Mitsubishi Heavy Industries, Ltd. (MHI) has received an order for a rubber tired automated people mover (APM)
system from the Land Transport Authority (LTA) of Singapore, and has made its first delivery of the originallydeveloped "Crystal Mover" APM vehicles. The "Crystal Mover" is an export version conforming to overseas market
needs, excellent in design, and people- and environment-friendly. For installation in Singapore, the standards andspecifications can be varied depending on the wishes of customers. This paper reports on the "Crystal Mover" and its
subsystems that assure safe and comfortable operation.

1. Introduction

2. Outline of APM system

In East Asian and Southeast Asian nations, there has
recently been an urgent need for convenient urban traffic services against the background of rapid urbanization.
At the same time, reduction of environmental load is a
global issue. These nations are promoting constructionof guideway traffic systems, including subways and newtransit systems. MHI received an order for the automatedpeople mover (APM) system for the Seng Kang andPunggol new town from the Land Transport Authority(LTA) of Singapore. The Seng Kang Line was opened in
January 2003, and manufacture of vehicles and construction of system are in progress for start of operation of
the Punggol Line in 2004. This paper gives an outline of
the APM vehicle of the system and its subsystems assuring safe and comfortable operation.

The APM system for Singapore's LTA is a feeder linefrom Seng Kang Station and Punggol Station of a new
subway North-East Line to New Town. Both the Seng
Kang Line and the Punggol Line are formed of two east
and west loop lines which converge at a subway junction station. The Seng Kang Line is 10.69 km long with
14 stations, and the Punggol Line is 9.47 km long with15 stations. The design transport capacity of the system is 2 100 PPHPD (passengers per hour per direction)in the Seng Kang Line and 2 700 PPHPD in the Punggol
Line.
This APM system, which is based on Japan's new transit system, consists of the vehicles and subsystems shownin Table 1
1.
Vehicles run by full-automatic driverless operation

Table 1 Composition of APM system
Subsystem

Function

Principal component

VehicleVehicleTransport unit

Operation control unit

Operation control unit

Operation and management of total
systemSignaling system

AVP/VD device

Signaling and safety function

Communication system

LCX transmission device

Communication between waysideand vehicle

Automatic operation system

On-board AVP/AVO device,station AVO device

Automatic operation of vehicle

Power distribution system

Transformer, power rail

Guideway

Running surface, guide rail,
switchStation facilities

Fare collection,
Fare collection system,
passenger information device passenger information service

Maintenance facilities

Depot, maintenanceequipment

Supply of electric power to system
and vehicle
Vehicle running line

(Note)
AVP/VD: Automatic Vehicle Protection/
Vehicle Detection
AVP:
Automatic Vehicle Protection
AVO:
Automatic Vehicle Operation

Vehicle maintenance facilities

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with automatic train control (ATC). The ATC is composedof automatic vehicle protection (AVP), automatic vehicle
operation (AVO), and automatic vehicle supervision(AVS). The AVP supports safe operation of vehicles suchas signaling safety equipment. The AVO controls automatic operation of vehicles. The AVS has functions ofoperation command, operation monitoring and operation
recording of the system.

seas markets on the basis of the technology of MHI's new
rubber tired transportation system. To meet varied transport needs flexibly, as compared with existing vehicles,
the size and speed have been increased, and the singlecar configuration is achieved. A prototype vehicle wasfabricated, the basic performance and functions wereverified, the interior and exterior design were proposed
for the Singapore project, the customer's desired specifications were incorporated in the product, and mass
production was designed.
The principal and new design items of the vehicle are
discussed below.
3.2 Vehicle aesthetic design
The vehicle is the system's core and also its face. The
vehicle aesthetic design (interior and exterior) is vitalfor passengers' first impression of the vehicle and thesystem. Today, the vehicle aesthetic design is an impor-

3. Development of APM vehicle

870

3 615

3.1 Outline of APM vehicle
The APM is a rubber tired vehicle. Carrying 105 passengers per vehicle, the driverless system is operated
fully automatically. The outline drawing of vehicle isshown in Fig
Fig.. 1 and its main specifications are given in
Table 22.
This APM vehicle has been newly developed for over-

6 700

1 850

11 2002 690

11 840Fig. 1 Vehicle configuration

Table 2 Vehicle specifications
Item

Specification

Configuration
Capacity

Single-car(passengers)

Vehicle mass

105 (including 18 seats)(t)

Vehicle dimensions (mm)Guide system

14.9/vehicle11840 long x 2 690 wide x 3 615 highSide guide two-axis four-wheel steering system

Electric system
Gauge

750 VDC(mm)

Vehicle performance

Gauge 1 850, guide rail span 3 200
Maximum speed
Vehicle performance: 80 km/h
Operation: 70 km/h
Acceleration: 1.0 m/s2 (3.6 km/h/s)
Deceleration
Maximum service: 1.0 m/s2 (3.6 km/h/s)
Emergency: 1.3 m/s2 (4.7 km/h/s)

.
.
.
.

Carboy structure

Aluminum alloy welded structure

Traction motor

Three-phase induction motor, continuous rating 80 kW X 2 units

Propulsion control system

VVVF inverter vector control (individual control of each axis)(with variable load control and regenerative brake)

Brake system

Electric command pneumatic brake with regenerative brake(with stand-by brake and parking brake)(with variable load control and wheel slide prevention control)

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tant element for enhancing the commercial value anddifferentiating it from other vehicles.
Against this background, the development of this APM
vehicle was participated in by industrial designers outside of MHI, and the job was consigned to a design teamfrom proposal to supervision of the vehicle design. In
cooperation with industrial designers, efforts were concentrated on both ideal design and productive function
and performance, and this APM vehicle was awarded theMinister Prize in the 32nd Machine Industrial Design
Competition in Japan.
3.2.1 Design concept
The concept of the vehicle aesthetic design is basedon the idea that this APM vehicle embodies the strategy
for transportation system export of the future. The keyword of the design is "Crystal." This has the concepts ofUniversal (common and general throughout the world),

Distinctive (different from others), Futuristic (forwardlooking), and Diamond-like (lasting for ever). In line withthis design concept, the vehicle was named "Crystal
Mover"; the trademark has been registered and is being
strategically advertised as a new product brand.
3.2.2 Exterior design
The exterior design is intended to embody the crystal
image of the vehicle. In particular, the nose is a dynamic
polyhedral profile making use of features of the APM
vehicle such as that no driver's cabin is required because
operation is driverless. The sides are not flat but have adelicate three-dimensional curve to soften the sharp
image of polyhedron, and a refined urban feeling isachieved. The car body is painted in pearl white and indigo blue, the window is harmonized in design, and abrilliant novel style is presented.
3.2.3 Interior design
The interior design is a fusion of the design concept
and the required functions of the cabin. Information forpassengers is provided in the corners of the cabin, andthe visual recognition and function are enhanced. Specifically, as we face toward the front of the vehicle, theline map and other operation service information are
shown in the left side corner, while the right side corner
is for emergency information, including the emergency
stop button, emergency notice system, and related caution and warning labels. In addition, an LCD information
display device is installed in each corner. The cabin
graphic design is a harmonious blend of customer requirements and designer ideas.
The cabin's side panels and ceiling are white, and thefloor is gray. The seats are grayish blue, and the handrails and grip bars are accentuated with a wine color.
This color scheme, which avoids metallic tones of whiteor gray, creates bright and friendly image for the cabin.
A view of the cabin is shown in Fig. 2
2.
3.3 Ride quality
The vehicle ride quality is determined by its vibration transmission characteristics and the irregularity (inquantity and wavelength) of the running surface. To realize comfortable ride quality, the vibration and vehicle
ride quality were analyzed in consideration of the irregular properties of the running surface. The design ofvehicle vibration transmission characteristic was optimized, optimum installation and management of runningsurface irregularity were executed, and good ride quality has been realized.
Concept of analysis for vibration and ride quality ofvehicle is shown in Fig. 33.
3.4 Vehicle crashworthinessIn the railway and guideway transportation system,
collision of vehicles is prevented by the signaling system, but in recent overseas projects, there has been an
increasing demand for vehicle crashworthiness aside
from the requirement for the signaling system. In thisFig. 2 Cabin interior
Infrastructure (running surface)

Vehicle characteristic

Guideway image

Vibration transmission
characteristic

Frequency (Hz)

Irregularity (mm)Acceleration (m/s2)

Analysis model

Irregularity of running surface

Distance (m)Acceleration (m/s2)

Vibration and ride quality of vehicle
Prediction of ridie quality

Frequency (Hz)Fig. 3 Concept of analysis of vibration and ride quality of vehicle

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3.4.2 Scenario of collision energy absorption
To assure safety in a collision, it is important to absorb the collision energy adequately and reduce its
impact. Fig. 4 shows a scenario of absorption of collisionenergy. The collision energy is absorbed by the shock
absorber of the coupler and the collision energy absorbing mechanism provided in the carbody (mechanical fusedescribed below). In particular, in the event of a collision that exceeds the buffering capacity of the coupler,
the two carbodies collide with each other, the collisionenergy absorbing mechanism provided in the front endof the carbodies is deformed and collapsed, the collisionload is suppressed below the specified value, and thecollision energy is absorbed uniformly and stably.
3.4.3 Collision energy absorbing mechanism
It is difficult to build a collision energy absorbing
mechanism of the carbody structure and optimize thecarbody structure while complying with other structuraldesign requirements. In this APM vehicle, therefore, aseparate collision energy absorbing mechanism (mechanical fuse) is attached to the carbody structure. Thismechanical fuse, based on a device developed by
Mitsubishi Fuso Truck & Bus Corporation for use in a

APM vehicle, it was required that in the event of collision of vehicles, the space between cabins should notcollapse and the collapse distance should not exceed one
meter.
Vehicle crashworthiness is a new technical field thatis not established sufficiently in vehicles of the railway
and guideway transportation system. In this Singapore
project, the latest automobile crashworthy technology
and design techniques have been introduced and adopted.
Essential points of crashworthy design are discussed
below.
3.4.1 Collision conditions and design target
In the APM system, collision of vehicles is prevented
by the signaling system, and it was attempted to set target values of collision conditions guaranteed in thevehicles and crashworthiness that matched the safety
performance of the entire system. These items are sum3 As shown in the table, it was deduced
marized in Table 3.
that collision of vehicles could occur due to human error
only in the case of limited manual operation. Target values were determined by matching them with the required
specifications related to crashworthiness, vehicle basic
specifications, and structural design conditions.

Table 3 Vehicle collision condition and design target
Specification

Item

Collision
condition

Operation condition

Manual operation with protection by on-board
AVP

Collision condition

Face to face collision of two vehicles of same
mass and at same speed

Vehicle mass upon
collision

Vehicle mass with normal capacity of passengers

Collision speed

11 km/hBias condition

Vertical direction offset
Lateral direction offset
In consideration of diagonal collision on curve
Not more than 0.5 m in nose of vehicle
Not reaching into cabin

Collapse distanceDesign target Absorption energy

110 kJ or more

Impact force upon collision

300 kN or less

Impact force
upon collision

Collision
Absorption of collisionenergy by coupler buffer
deviceCoupler tear-off due to
breakage of coupler mounting bolt

Energy absorption bymechanical fuse

Coupler tear-off
Strength ofcarbody underframe
Energy absorption bycoupler buffer device

Absorption of collisionenergy by mechanical fuse

Deformation
Collapse distance of
mechanical fuseFig. 4 Scenario of absorption of collision energy

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nuclear fuel transport truck, is a perforated conical steel
tube structure. In its mechanism, the tube buckles anddeforms due to the collision load applied to the front end,
Fig. 66).
and hence absorbs the collision energy (Fig.
Two mechanical fuses are provided under the front
end of the carbody. The front end structure of the carbody
has directivity in deformation and collapse mode by perforation so as to maintain strength against normal load
and be likely to collapse against collision load.
3.4.4 Design and verification of crashworthy
mechanism
Fig. 5 shows the general flow from design to verifica-tion of the collision energy absorbing mechanism for the
APM vehicle.
Following the basic design, the mechanical fuse was
evaluated by CAE analysis and element testing to execute detail design and verification at the same time.
Analysis and element test are executed repeatedly ateach step and the design is improved until the initial
aim is satisfied. As for the mechanical fuse, collision testof the fuse was executed, and dynamic collapse characteristics and buckling mode were verified. Fig. 6 shows
comparative analysis and test results of the fuse in the
deformation mode. As shown in Fig. 6, the analysis andtest results coincide well in the deformation mode. Regarding the collision energy absorbing characteristics,
the analysis and tests results also coincide very well,and the design target is satisfied. The mechanical fuse
was thus shown to have the designed collision characteristics, and the validity of CAE analysis was also
verified.
Finally, the whole vehicle provided with mechanicalfuses was evaluated for its collision characteristic. Onlythat which had been already confirmed to be valid wasverified by the CAE analysis, and no test with the actual vehicle was conducted. Fig. 7 shows the analysis
results of face to face collision in a straight line. As shownin the figure, the collapse distance of the vehicle structure after collision is 0.27 m, which satisfies the design
target of 0.5 m.
Stable deformation and collapse were also confirmed.
Diagonal collision on a curve was also evaluated by CAE
analysis, and favorable results were obtained.
Thus, the collision energy absorbing mechanism forthe vehicle was designed and verified by effectively uti-

Scenario of absorption of collision energy
Conceptual design

Basic design

Collision test of
mechanical fusealone (element test)

Elastic-plastic FEM analysis ofmechanical fuse alone(static analysis & dynamic analysis)

Elastic-plastic FEM analysis ofbody front end structure(static analysis)

CAE analysis

Collision analysis on whole body(dynamic analysis)

Evaluation
Fig. 5 Design flow of collision energy absorbing mechanism

0 (ms)

60(ms)

10(ms)

80(ms)

20(ms)

100(ms)40(ms)

140(ms)

FEM analysis

FEM analysis
Element test
Fig. 6 Deformation process of mechanical fuse

Element test

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Vehicle conditions

Deformation statusof vehicle front end

Collision
speed: 11 km/h

AVP
receivingdeviceAVP
control device

Brake command

AVO
transmitting
and receiving
deviceAVO
control device

Powering command
Brake command

AVO antenna

Speed generator

AVP antenna(a) Conventional configuration

Vehicle conditions

AVP/AVO control device

AVP
receiving device

AVO
transmitting
and receiving
deviceMechanical fuse
270mm
Collapse distanceFig. 7 Analysis result of vehicle collision

AVO antenna

AVP/AVO
control
processed

Powering command
Brake command

Speed generator

AVP antenna(b) Integrated configuration of AVP and AVO
Fig. 8 Configuration of on-board automatic operation control systemlizing CAE analysis and element testing, and favorable
results satisfying the design target were obtained. At thesame time, by use of the reliable CAE analysis, it waspossible to omit expensive actual vehicle testing, thedevelopment period was substantially shortened and thecost was reduced.
3.5 Integration of on-board automatic vehicle
protection and operation (AVP, AVO)
Signaling and automatic operation system conform to
the new transit system in Japan. The on-board devicesof which these systems are composed are original devicesof APM vehicle for full-automatic driverless operation.
These devices were reduced in size and mass in order tobe assembled in the limited equipment space of the cabinduring the development of the APM with single-car andsmall body.
The conventional equipment composed of independent
devices made by different manufacturers was reviewed,
the functions were integrated, and on-board control devices were united and reduced in size and mass.
Specifically, safety protection devices such as the AVP
receiving device and AVP control device, and the AVO
control device necessary for automatic operation are integrated into one unit by reducing their size and mass,and the equipment wiring was simplified.
Fig. 8 (a) is a block diagram of conventional on-board
control equipment. As shown in the diagram, the AVP

control device and AVO control device have common
points in input and output signals such as speed generator input and console input. Making use of these points,
the CPU and hardware are shared by the AVP control
device and AVO control device, and the AVP receiving
device is also incorporated into the same housing. As aresult, control from reception of AVP signal to train control and automatic operation can be realized by one
device as shown in Fig. 8 (b).
The AVP is a safety protection device for assuringsafety of the train, and the AVO is a device for automatic
operation. To integrate these two functions whose purpose and nature, are different, the most important point
is not to sacrifice the function of the AVP, which is a vital safety protection device. In this respect, the concepts
were summarized as follows.
(1) The safety-related software of AVP is isolated fromthe AVO, and its safety is assured.
(2) The AVO operation is executed in the idle time of the
AVP program (while the CPU is not being utilized),
and the AVP and AVO are completely independent infunction and control logic.
(3) Sharing of variables between AVP and AVO is prohibited. However, the AVO is allowed to refer to theprocessing results of the AVP.
As a result, the software of the equipment is clearly
separate and independent in the functions of AVP and
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Start of process

Start of process

Start of process

Failuredetection
process

Failuredetection
process

Failuredetection
process

Input and
outputprocess

Input and
outputprocess

AVO
process

AVP
process

End of process

End of process

Input and
outputprocess

AVP/AVO
integration

AVP
process

AVO
process

End of process
Conventional software
configuration of separate
AVP and AVO
Integrated software of
AVP and AVO
Fig. 9 Concept of software integration of AVP and AVO

AVO, and the role and safety as safety protection device
are guaranteed.
The arithmetic processing of the software is a singlethread structure for processing a series of programs
sequentially in series conforming to the conventional
single constant period interruption. For integration, processing of two functions of AVP and AVO is required, butthey are not processed in parallel, and the single-thread
structure is employed. This means that after AVP-related
processing, AVO-related processing is added programmed
to execute them in series. Complication of the program
structure is thus avoided. The concept of integration ofsoftware is shown in Fig. 9
9.
AVP control function is parallel duplex system, and
AVO control function is waiting duplex system, and thereliability is thus enhanced. Although AVP control and
AVO control operate in the same CPU system, since thefunctions are separate for AVP and AVO, troubles are also
divided into two types related to the AVP and to the AVO.
Self-diagnosis of hardware (trouble check of CPU, etc.)
is a function of the AVP, and if the fault is judged to be a
result of checking, it is changed over to another system.
Troubles of AVP include common hardware troubles of
AVP and AVO, and the AVO is simultaneously judged to
be defective.
In the AVO-related functions, only the input and output hardware used in the AVO is checked for trouble. If
as a result of checking it is judged to be input and output failure, it is understood as AVO trouble, and all
AVO-related outputs are cut off to change over to another system. However, the control of the AVP continues
as usual, and with this software and hardware configu-

Vehicle condition
Speed signal

AVOtransmitter/receiver

AVP controller
AVO controller

Control output

AVP
normal

AVP control content
acquisition
Normalrelay
control Control output

Structure of
hardwareHardware selfdiagnosis result
Normal relay
control

AVO
controller

Brake command
Stop detection

Structure of software

Input interface

Powering command
Brake command

Fig. 10 Integrated function of AVP and AVO

ration, the AVP-related function is not lost and the control can be continued. This relation is shown in Fig
Fig.. 1010.
Thus, by integrating the functions, hardware and software of the on-board automatic operation control devices(AVP, AVO), the equipment is reduced in size and massand the functions are integrated.
3.6 Conforming to overseas specifications andstandards
The basic performance and function of full-automatic
Mitsubishi Heavy Industries, Ltd.
Technical Review Vol.40 No.3 (Jun. 2003)7driverless operation of single-car has been verified andconfirmed by a prototype vehicle. Prior to start of mass
production for overseas markets, the products must satisfy the individual specification requirements andapplicable standards in various overseas projects. The
aesthetic design and collision safety are characteristic
requirements in overseas markets today, and others are
discussed below.
3.6.1 Air conditioning system
Singapore has a tropical climate, and performance andcapacity of the air conditioning system are indispensable requirements. The cooling capacity is designed at
32 kW in the vehicle with capacity of 105 passengers inorder to keep the cabin in the condition of 26oC DB and
60% RH while taking in fresh air at 0.175 m3/sec in an
ambient condition of 34 o C DB and 75% RH. As the air
conditioning equipment, a thin built-in roof type has beendeveloped to match the vehicle exterior design, and twounits are incorporated in the roof at both ends of thevehicle.
To verify the performance of the air conditioning system, in addition to the cooling capacity test on a air
conditioner, an environmental test was conducted simulating the environmental conditions of Singapore(temperature, humidity, solar gain, etc.) by using an actual vehicle in the MHI's environmental test laboratory.
As the refrigerant, substituent chlorofluorocarbon R407C
is used to lessen the global environmental load.
3.6.2 Fireproof performances
Vehicles are required to be fireproof, and the standard in force overseas is strict. In this APM vehicle, thebody structure is required to conform to NFPA 130 andits cited standard ASTM. In particular, the floor structure is defined according to the combustion temperaturepattern specified on the basis of ASTM E-119, by which
the average temperature rise of the floor may not exceed 139 o C in 15 minutes as a result of heating andcombustion from under the floor. To satisfy this standard, a heat resistant sub-layer of insulating material
was provided in the lower side of the underframe structure, and heat conduction to above the floor was
suppressed. The fireproof performance was verified byusing a full-size floor structure including heat resistant
sub-layer and having a combustion test conducted by athird party organization. In addition, interior material
and others are also made of materials conforming to thefireproof standard.
3.6.3 Front penetration test
In overseas project, the strength against flying object
hitting the front of the vehicle is often required. In thisAPM vehicle, it was required that an object should not
penetrate the front glass or the front structure if hit by
the corner of a hollow cubic structure of mass of 0.9 kg
and 75 mm on one side specified in BRB/RIA 20 at twiceof vehicle speed. To satisfy this requirement, the front

Slot formutual access

Vehicle for west loop

Slot for mutual access

Vehicle for east loop

West loop

East loop

Town Center station(linked to subway)
Fig. 11 Concept of synchronous control at convergence point

glass is an aircraft windshield and the other front structures are made of FRP. By verification tests of thematerials, the penetration performance was confirmed.
3.6.4 Electromagnetic compatibility
Electronic devices are recently being used for various
purposes. The circuits are complicated, and electromagnetic interference between such devices is often reported.
Accordingly, there is a mounting demand for electromagnetic compatibility (EMC) - that is, electromagnetic noise
should not be emitted from the devices and the devices
should not be influenced by incoming electromagnetic
noise. This APM system was required to conform to the
EN standard. In compliance with the standard, EMC
tests were conducted on the individual on-board devices,
the whole vehicle, and wayside subsystems. As a result,a satisfactory EMC performance was confirmed.

4. Construction of subsystems
4.1 Operation control system
The operation control system conforms to the newtransit system in Japan. In the operation of this APM
1 , trains running clockwise
11
system, as shown in Fig. 1
and counterclockwise in east and west loops meet at theunderground junction station (Town Center). In the existing railway or new transit systems, independent
platforms were installed for the east and west loops at
the station corresponding to Town Center, and independent line operations were conducted. In this APM system,
however, tall guideway structures must be minimized inconsideration of the peripheral urban development andother circumstances. Accordingly, independent platforms
were not constructed at Town Center station, and theoperation management system was designed to allow
trains of the east and west loops to use a common platform.
For such operation, the operation intervals on thebasis of the transport capacity defined in the east andwest loops must be synchronized at the line convergencepoint. To meet this need, the concept of synchronous control shown in Fig. 11 is employed. In this synchronous
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4.3.2 Guideway structure
Guide rails are installed on both sides of the guideway to guide the vehicle from both sides. At equalintervals, guide rails of H-section steel are installed.
The power rail is installed on one side of the guideway, and 750 VDC is supplied to the vehicle. The power
rail is held at equal intervals together with the guiderails by means of common brackets. The conductor isaluminum, and stainless steel is used on the sliding surface as a wear-resistant material.
A total of 37 switches are installed, 16 on the mainlines and 21 in the depot, and all are remote-controlledfrom the operation control center room.
To indicate the turning direction of the switches formoving the working vehicles at the time of maintenance,a simplified lighting system (line side signal) has beendeveloped. The status display of the signaling machineis indicated by stop, straight ahead, or left (right) bylighting up one signaling machine. The signal is realized by high luminance LED featuring long life, breakage
resistance and easy recognition night and day. Further,since the contact point is shared, it is synchronized withthe change of the switch by a signal from the operation
control center room.
4.4 Maintenance equipment
The depot is adjacent to the Seng Kang Line, and islocated on the second floor of the depot of the subway
system. The total area is about 3.5 ha, including 21
switches, 8 buffers, 6 vehicle inspection lines, maintenance space, two-story main building with operation
control center room, automatic vehicle washing facility,
maintenance garage, departure inspection track, stabling
yard, power receiving and transforming facilities, andtest track for running test after overhaul.
4.5 RAMS
For export of the transportaion system, prior evaluation of reliability and safety of the system is a technicalrequirement. In this APM system, analysis of RAMS was
introduced and executed for evaluation of the Reliabil-

control, the train is placed in a position called a slot at
the minimum operation interval specified by the customer, and this is coordinated with the middle slot of
the opposite side line. In the converging point of the Town
Center entry side, block division and signal indication
assignment for increasing the operation density between
the convergence point and Town Center were implemented in order to control operation at half of theminimum operation interval. Furthermore, to prevent
traffic congestion in this section, a departure reduction
function was incorporated to adjust the train departure
timing at the station before the convergence point using
a station control device.
4.2 Electric power distribution system
The electric power distribution system is designed toreceive three-phase 50 Hz electric power of 22 kV, at areceiving substation from a host substation, and to distribute the 22 kV power directly to each station. At eachstation, the 22 kV is stepped down to 400/230 VAC by alocal transformer, and distributed to the facilities of thestation as necessary. A feeding substation is installed atthe vehicle center, the east loop and the west loop. Eachfeeding substation includes a rectifier and an inverter,and 750 VDC is fed to the vehicle. Usually, the power is
supplied to the depot, the east loop and the west loop
from each feeding substation, but if one substation fails,
by closing the switch provided at the convergence pointof the east loop and west loop, power can be supplied
from the other substations.
4.3 Guideway and guideway facilities
4.3.1 Guideway geometric design
This APM system is installed in a suburban new town
district, and includes loop line formation and cloverleaf.
A complicated guideway geometric design, includingalignment and profile, was required. From the stage oftown planning by construction consultants, original
guideway geometric plans and corrective ideas were proposed by simulation, and comfortable ride quality wasrealized by limiting speeds due to guideway restrictions.
The procedure is shown in Fig. 1212.
(1) Making provisional outline of guideway geometricpattern (proposal by construction consultants).
(2) Evaluation of outline of guideway geometric patternby running simulation in consideration of operational
criteria and vehicle characteristics.
(3) Evaluation of outline of guideway geometry, extraction of alignment and profile elements such as
restraint conditions from run-curve, and change ofalignment and profile objects to be studied.
(4) Re-evaluation of outline of guideway geometry byfurther simulation.
(5) Determination of outline of guideway geometric pattern when evaluated favorably.
These five items were repeatedly studied for each station and the outline of geometric pattern was optimized.

Making of provisionalguideway geometric pattern

Guideway geometry evaluation
by running simulation

No

Simulation according to criteria

Proposal for improved
guideway geometric pattern

YES
Determination ofguideway geometric patternFig. 12 Optimization routine of guideway geometric design

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Technical Review Vol.40 No.3 (Jun. 2003)

9ity, Availability, Maintainability, and Safety. This RAMS
is divided into RAM and S.
In the reliability analysis, using the analytical technique of failure mode effect & criticality analysis(FMECA), the mean time between failures (MTBF) of theentire system was calculated from the MTBF of each line
replaceable unit (LRU).
In the maintainability analysis, using the analyticaltechniques of preventive maintenance analysis (PMA)
and corrective maintenance analysis (CMA), the meantime to repair (MTTR) of the entire system was calculated from the MTTR of each LRU.
In the availability analysis, the availability was calculated from the obtained MTBF and MTTR of the entires y s t e m . Av a i l a b i l i t y i s e x p r e s s e d b y M T B F /(MTBF+MTTR). It was confirmed that the result satisfies the required values of availability by 99.00% in
vehicles, 99.98% in signaling system, and 99.99% in distribution system.
Safety was analyzed on the basis of the standards of
MIL-STD-882C and DEF-STAN-0056.
First, possible hazards occurring in the system werelisted. Next, the frequency of incidence of hazards, anddegree of damage by hazard were evaluated. The frequency of incidence and degree of damage were classified
in six ranks and four ranks, respectively, depending on
the severity. The degree of risk is estimated from theranking of the frequency of incidence and degree of damage.
In each classified risk, safety was analyzed. For safety
analysis, the three known techniques are subsystem
hazard analysis (SSHA), interface hazard analysis (IHA),
and operation & maintenance hazard analysis (OSHA).
The SSHA mainly handles hazards caused by trouble ofdevice or unit. The IHA analyzes hazards caused bytrouble or defects of interface between subsystems. The
OSHA deals with hazards occurring during operation or
maintenance control.
By using such procedures and analysis techniques,
about 1 400 items of hazard were analyzed by SSHA,

about 800 items by IHA, and about 700 items by OSHA.
As for high-risk hazards discovered in the process ofanalysis, proper measures were taken and the risk was
lowered. As a result, the hazard risk of the entire system was reduced, and it was confirmed to be free frominconvenience in operation as a transportation system.

5. Conclusion
The Seng Kang Line of APM system for Singapore's
LTA started revenue service in January 2003. An outline of the APM vehicles and subsystems supporting themis presented in this paper. MHI hopes that this system
will be accepted widely by Singapore people, together
with its nickname Crystal Mover, and that it will achieve
the specified target as an urban transportation system.
MHI express its deepest gratitude for the help andadvice it received in the completion of this APM system.
MACHINERY HEADQUARTERS

Hiroyuki Mochidome

Masahisa Masukawa

Yasuyuki Suzuki

Makoto Kashiwa

NAGASAKI SHIPYARD &MACHINERY WORKS

Shinichi Sadamitsu

HIROSHIMA RESEARCH &DEVELOPMENT CENTER

Hiroyuki Kouno

Mitsubishi Heavy Industries, Ltd.
Technical Review Vol.40 No.3 (Jun. 2003)

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