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by: Bassam Mansour


Signaling & Train Control (S&TC) System represent the life blood of any railway.  The design, installation and effective testing and commissioning of the S&TC is a safety-critical activity that can’t be overemphasized. This paper looks at the background to signalling and the evolution towards digital railway in Malaysia, in particular the Communication Base Train Control (CBTC).

Control software is at the heart of the CBTC system, therefore, its development and testing plays a vital role in railway safety and the precision of its operation. The paper emphasis the significance of software validation and verification before opening the system for public use.  The paper describes CBTC architecture, interfaces and integration challenges with other railway systems including Rolling Stock and track system, migration strategies from legacy systems to CBTC, system assurance, CBTC Operation, Maintenance and training regime.  The contents of this paper was presented at Rail Solutions Asia conference in Kuala Lumpur in May 2017.


1  Introduction

The original signaling control system goes back to the late 1800 when the Track Circuit was first introduced by the Irish born William Robinson (1840–1921). Track Circuit is a vital component of the signalling system that is used to detect the presence or absence of trains on the track, it displays the status of the track on trackside signals to alert train drivers about the condition of the track ahead. See figure 1.

Figure 1: Management of Cybersecurity threats

The use of track circuit system with aspect signals is widespread and well used in the majority of the mainline railways and freight worldwide as well as some urban and suburban railways (e.g. Millburn Metro Trains).   Track circuit system is also referred to as fixed block signalling with predetermined signaling section lengths that limits the number of trains in any one section. By and large, this system relies on the driver to interpret the line side signals and control the train accordingly.

With the advent of digitization, automation and emergence of the CBTC in the early 1980s, more and more railway authorities are adopting the CBTC system due to its superior capability to handle heavy traffic, short headway, short dwell time, and high-capacity urban transit systems such as Monorails, Metros, and LRTs etc.

The CBTC doesn’t rely on the driver to interpret track conditions as the system is entirely automatic and programmed in accordance with predetermined operational scenarios.  This paper gives some insight into the practical application of CBTC systems in Malaysia, it examines CBTC architecture, interfaces and integration challenges, migration from legacy to CBTC strategies, system assurance, and identify the key CBTC Operation, Maintenance and Training Regime necessary to implement CBTC.


2   Towards Digital Railway

There are various operational scenarios that govern the application of the CBTC system, all of these scenarios are digitally programmed, tested, verified and validated through the use of high-level software language that maps out the track alignment data, track parameters and commands the train propulsion system in real-time using fully redundant microprocessors based controllers.  The behaviour of the train movement is fully controlled and predetermined by train on-board equipment such as Automatic Train Control (ATC) or Vehicle On Board Controllers (VOBC). According to IEC 62290 CBTC Grade of Automation (GoA), there are 4 GoA operational principles used in the CBTC system as depicted in table 1 below:

Note: The terms used are defined as follows:  UTO – Unattended Train Operation, ATP – Automatic Train Protection, STO – Supervised Train Operation or SATO – Semi-Automatic Train Operation



In Malaysia Kelana Jaya Line and MRT line 1 are fully automatic using GoA4 control, whereas the Ampang Line uses GoA2 and the MRT Lin2 that is currently under construction will be GoA4. The CBTC system is based on the moving block principle, in which the system creates a protection envelope for each Light Rail Vehicle (LRV), which is dynamically updated based on train location, speed and direction. This means it is possible to berth many trains on the line thereby improving the headways, increasing the train fleet size and catering for higher ridership capacity. Figure 2 depicts the CBTC System Architecture that was used on the Ampang Line. The system was equipped with Zone Controllers (ZC), track mounted tags and uses radio communication between trackside equipment on the train.  Zone Controllers are displaced and located at strategic locations on the trackside and interconnected via a fibre optics backbone network.

Figure 2: Ampang Line CBTC System Architecture


The entire railway system is controlled from Operation Control Centre (OCC) that monitors the movement of trains in accordance with a commercial timetable.  See figure 3 showing the OCC at Ampang.

Figure 3: Operation Control Centre (OCC) at Ampang

Protection of the network from Cyber threats is an essential component of the CBTC design, in the Ampang Line the CBTC system had inherent cybersecurity safeguards that includes three levels of protection, namely: Security Devises (SD) which controls access to the network e.g. wayside backbone or On-board network, Certificate Authority (CA) which supplies all SD information and their configuration and finally Interface Filter (IF) which acts as a border gateway and safeguard against external sub-networks.  Figure 6 shows the extent of the cybersecurity protection.

Migration from Legacy to CBTC

The migration strategy to convert a legacy system into digital CBTC system is based on a collaborative approach between the CBTC system suppliers and the operator and maintainer, without which it would not be possible to deliver a successful migration plan particularly when the existing railway operations are kept running.

For the Ampang line the strategy was based on three pillars:

  1. Communication with the public to inform them about the system upgrade to CBTC ;
  2. Collaborative working with operators and maintainers and coordinate the programme of implementation especially when most of the work was performed during engineering hours; and
  3. System Integration Test (SIT) that covered all operation scenarios.

Once the above was implemented and successfully completed the CBTC providers issued a Safety Certificate for opening the system for use.

CBTC System Assurance

The CBTC is a microprocessor based system, therefore, the validity, integrity, reliability and safety of the software developed for the project application is fundamental to safe operation of the railway. Sufficient testing and simulations as well as trial testing must be performed as a matter of necessity and prerequisite to acceptance of the railway.  Witnessing the simulations and field test are important for the operator and maintainer familiarization and understanding of the system. The following prerequisites are essential prelude for acceptance of the software:

  • Confirm that software source code has been verified and approved by a recognized third party test house.
  • Check that software for the Automatic Train Supervision (ATS), on-board equipment, trackside equipment are all compatible and correctly interfaced (e.g. radio and Data Communications System (DCS), Passenger Information Display System (PIDS), ATS, Points and Crosses (P&C)).
  • Rolling Stock brake system behaviour and response is compatible with CBTC software with no long time delays that affect the behavior of the brake system
  • Software configuration is controlled and software versions and issues are monitored and controlled

Ensure that Software is tested through laboratory test simulations and demonstrate all timetable operating scenarios under normal and degraded modes. The overarching standards covering the entire CBTC system are depicted in Figure 4.

Figure 4: Overarching Approach to CBTC Functional Safety Systems Assurance
based on International Standards


Interfaces and integration challenges

The entire railway subsystems such as track, signaling, rolling stock, communication and power should all work in consort to ensure a fully integrated railway that is operationally responsive and predictable. Key aspect of CBTC delivery is the on-board antennas and their interaction with lineside radio, this aspect of integration is critical to the working of the railway.  Refer to Figure 5 for illustration of the challenges.

Figure 5: Integration and interface: Antennas compatibility
WIFI Based 2.4GHZ (or 5.1-5.8GHZ)


Operation and maintenance requirements

The adoption of CBTC system is not just a change in technology, it is an organizational change that requires operators and maintainers to be familiarized and competent in the operation and usage of CBTC technology. Knowledge of computer based technology including management and modification of the CBTC application software is necessary to keep the railway running to an optimum standard and meeting the regulatory authorities Key Performance Indicators (KPI).

The CBTC microprocessors based equipment and components are so designed to provide intelligent information about their status and also ensuring the system is fail safe.  Failure management competency is necessary to cater for the three possible failure scenarios as follows:

  • ATS failure at OCC;
  • Trackside failure of CBTC components; and
  • Train onboard equipment failure such as VOBC or ATC.

 Operational Management of a fully-automated metro system- Training

Training of the operator and maintainer (O&M) on the new CBTC system is paramount, and investment in such endeavour over weighs the cost. The O&M strategy adopted in Malaysia covers three critical layers of management as follows:

  • Supervision and management of operations;
  • Control of operation; and
  • Securing Operation.

Figure 6 illustrates the O&M strategy.


Figure 6: Operational Management of a fully-automated metro system- Training



This paper has provided an outline of the development of the CBTC system, provided an insight into practical examples that have been implemented in Malaysia.  The CBTC continues to improve particularly with regards to radio communications, track data management, configuration of the system, adoption of WI-FI and LTE communications. Keeping up with technological changes is a key organisational development of modern O&M organisations.



I wish to thank RailAsia for inviting me to write this article for the purpose of disseminating knowledge and sharing information and experience with others in the railway Industry in SEA region.

I also wish to put on record my thanks to HSS Engineering Sdn Bhd, Malaysia for supporting me in the writing of this paper.

Pusat Rehabilitasi PERKESO is the first rehabilitation complex in the world that combines medical and vocational rehabilitation with an allied health institute. Under PERKESO’s ‘Return to Work’ programme, disabled patients undergo physical and vocational rehabilitation in order to rejoin the workforce. Located on 55 acres of undulating landscape, a ‘primary spine’ for walking, wheelchair and buggy linked the various clusters of buildings sequentially.

This green certified complex (under the Malaysian ‘Green Building Index’) was designed where nature via lush expansive landscape and ‘spirituality’ is an important element integral to the healing process. Employing universal ‘access for all’ concept and Malaysian Standard (M.S), this project was intended to represent the best planned rehabilitation facility suited to international standards.

The surrounding area is located in the development of Bandar Kesihatan dan Pendidikan Hang Tuah Jaya which will be a medical hub of the state. The area known as the green lung of the Melaka state is suitable for therapeutic, psychological and rehabilitation environment being an advantage for the PERKESO Rehabilitation Center to be able to offer a holistic approach in rehabilitation.

HSS Integrated Sdn Bhd has played an integral role in the success of this project by providing consultancy services for civil, structural, mechanical and electrical works for the design and construction of the overall buildings, infrastructure and utilities.



The KL-Kuala Selangor Expressway (LATAR Expressway) linking Kuala Lumpur at Templer’s Park in the district of Gombak with the township of Ijok in the district of Kuala Selangor on the West coast of the peninsula, was opened on Thursday 23 June 2011.

The 33 km dual carriageway expressway is the alternative link road to the present Jalan Sungai Buloh – Kuala Selangor (Federal Road 54). Now opened, LATAR Expressway provides for a faster, safer, smoother and non-congested drive that would take just a brief 18 minutes to accomplish from end-to-end. Commuters will find easy access, convenience and connectivity to the many communities and townships along the LATAR Expressway.


The LATAR Expressway features four interchanges and three toll plazas on each side of the expressway. The four interchanges give faster and easy access into the existing Guthrie Corridor Expressway, PLUS North-South Expressway and the future West Coast Highway.

HSSI was appointed as Project Management Consultant for the KL-Kuala Selangor Expressway which is part of the KL Outer Ring Road linking the coastal area in the north-western region of Selangor and the northern region of Kuala Lumpur.

The South Klang Valley Expressway or SKVE is an expressway in the southern part of Klang Valley, Malaysia’s most densely populated region. This 51.7 km (31.7 miles) dual-carriageway provides links to the booming towns in southern Klang Valley, including the country’s administrative capital, Putrajaya. Section 1B of this expressway between Cyberjaya to Bandar Saujana Putra was opened to traffic on 1 July 2010.

HSSI was appointed as Project Management Consultant for the SKVE.


The MRT Project

The main challenge facing the deteriorating urban transportation in the KL metropolitan area is the unsustainable growth in private transport demand. This challenge is made tougher by the declining public transport mode share. The reasons for the decline in public transport ridership include inadequate rail coverage, insufficient connectivity, stations in low-demand areas, unsatisfactory bus network system and poor interchange between modes. KL is lagging far behind other world class cities in terms of public transport ridership and the congestion in the city is escalating at an alarming rate.

The Government acknowledges that the long term solution to improve the current urban transportation problem is to introduce a mass rapid transit system, with a seamless integration with the other forms of public transport, i.e. KTMB, LRT, Monorail and Feeder Bus systems. In 2010 the Government formed a single regulatory body – Land Public Transport Commission (SPAD) – to plan and coordinate all the different forms of land public transport in the country. MMC-Gamuda JV submitted a comprehensive proposal to the Government in 2010 for the implementation of the Klang Valley Mass Rapid Transport (MRT), basically proposing two radial lines between the NW and SE corridors through the City Centre and supplemented by a radial line connecting all the existing and proposed radial lines. The main objective of this proposal is to achieve a targeted 50% peak hour public transport modal share by 2025.

The Government has so far agreed to implement one of the radial lines, i.e. from Sg. Buloh to Kajang (SBK). The Government has appointed Syarikat Prasarana Negara Berhad (SPNB) as the asset and project owner of the MRT Project and MMC-Gamuda as the Project Delivery Partner (PDP). The principal role of the PDP is to manage the planning, design, procurement, construction, integration, testing and commissioning and eventual handover of the project to SPNB for operations. In undertaking this role, the PDP carries with it certain cost and time liabilities.

The SBK line is 51 km long, with 41.5km elevated and 9.5km underground (tunnel). 31 new stations (and 4 future stations) are proposed for the SBK line, out of which 11 stations will be interchanges with existing and future rail lines. 7 of these stations will be underground. There will be 16 potential Park & Ride sites provided, and improved access to new and emerging centres and development sites, such as RRI, Warisan Merdeka, Pudu Jail Redevelopment, Kuala Lumpur International Finance District and Cochrane Redevelopment.

SPNB has issued an LOI to HSS Integrated Sdn Bhd in a JV with SNC Lavalin (of Canada) to take on the role of Independent Consulting Engineer (ICE). The ICE has submitted its technical and commercial proposal to SPNB and this is being finalized. In the meantime, the ICE has been tasked to proceed with its roles and is already actively involved in the Project.

HSSI was previously involved in the design, construction and supervision of the Kuala Lumpur International Airport (KLIA), the Light Rail Transit System 2, the North-South Expressway, Maju Expressway and the Express Rail Link (ERL). These successes have given HSSI a proven track record in leading as the ICE for the SBK line, which is estimated to cost about RM 20 billion.

The role of the ICE is crucial as it will provide the Government with advice on all the crucial issues and will act as “checks & balances” on the implementation and management of the Project by PDP. The ICE’s role will cover design review, providing an oversight on the construction activities, including tendering, quality and safety assurance, progress monitoring and advising a smooth and seamless transformation of the project into its operational mode. The ICE will also be involved in the underground works (tunnelling and underground stations), which is said to be worth about RM8 billion (40% of the total project cost).

According to the figures forecast by the Performance Management and Delivery Unit (Pemandu) of the Prime Minister’s Office, the contribution of the MRT Project to Malaysia’s gross national income (GNI) will be phenomenal. The MRT project when fully completed by 2020, is estimated to contribute up to RM21 billion per annum to the GNI. The increase in GNI will be from the jobs created during the construction of the MRT, increased productivity of workers and appreciation of property values. Pemandu estimates that approximately 1.2 million sq. ft of commercial and residential space will enjoy appreciation in gross development value.

One of the major developments that will gain substantially from the MRT is the RM26 billion KL International Financial District project which covers 75 acres between Jalan Tun Razak, Jalan Sultan Ismail and the Putrajaya elevated highway. The MRT will also run through the proposed 100 storey Menara Warisan located near Stadium Merdeka which will also house SPNB’s offices when completed.

Once again HSSI takes an important role in nation building. The MRT is considered to be the single largest infrastructure project undertaken by Malaysia and it will receive valuable and efficient input from HSSI playing the lead role as the Independent Consulting Engineer.