The achievements in tunnelling and underground space development in Malaysia, in the past one and half decades are impressive. From the very beginning of the older tunnels constructed associated with the construction of dams (e.g. Kelinci Dam water transfer tunnel, diversion tunnel of the Sg. Selangor Dam, pressure tunnels and powerhouse for the Pergau Dam, etc.) and highways (e.g. Karak Highway twin tunnels and Penchala Link twin tunnels) and on to the subway Light Rail Transit (LRT) system, tunnelling activities have been gaining momentum in the 21st century with the construction of the Storm Water Management and Road Transport System (SMART) dual-purpose tunnel, Pahang-Selangor interstate water transfer tunnel, double tracking electrified railway tunnel and the most recently completed is the Klang Valley Mass Rapid Transit (KVMRT) from Sungai Buluh to Kajang as well as the planned High Speed Rail (HSR) and the East Coast Rail Link (ECRL) projects.


Karak Highway Twin Tunnel

Sungai Selangor Water Transfer Tunnel


Recent development in Variable Density TBM, conceptualised by Malaysian owned companies MMC-Gamuda JV through exhaustive research and collaboration with TBM manufacturer Herrenknecht AG and Ruhr-University, is the first-of-its-kind in the world of the tunnelling industry. VD TBM has proven to be an effective boring machine to excavate in different types and yet challenging geologies and performed beyond expectations when it successfully endured the tunnel drives in the Klang Valley MRT Project through underground karstic formation without any incident of the dreaded sinkholes or blowouts.


Variable Density Tunnel Boring Machine


It is also worth noting of the success in setting up a world’s first tunnelling school, also known as the Tunnelling Training Academy (TTA) in record time in December 2011. This was to response to an urgent call to create a high-income employments as Malaysia is shifting into high-gear as the nation enters into a new era of economic transformation to achieve the coveted developed nation status by the year 2020; as well as to realise its need to create a sustainable pool of certified tunnelling workforce to cater for new phases in the ongoing massive Klang Valley Mass Rapid Transit (KVMRT) project. TTA is the answer to meet the needs of the mega KVMRT project; as well as to create a sustainable technology-based industry to nurture expertise and boost productivity in tunnel engineering, enabling local players to take on more complex tunnelling construction projects in the future.


Tunnelling Training Academy (TTA) Opening Ceremony in 2011


The following is a list of tunnelling projects recently completed in Malaysia and the projects in the pipeline together with their contribution to the advancement of the underground construction industry as a whole.

Tunnelling Activities in the Recent Past

Storm Water Management and Road Transport System (SMART)

SMART Tunnel

An example of a successful urban underground development to help solve urban problems, the innovative SMART project is a dual-purpose tunnel. The project provides a storm water diversion scheme including flood-water storage reservoir and a 9.7 km long by 11.8 m diameter bypass tunnel, sufficient to spare the Kuala Lumpur city centre from severe flooding at times of inclement weathers in future. Though no major flood events over most of the past years. The dual-purposes tunnel was engineered, with a waterway beneath a double-decks motorway built into a central 3 km  long section, relieving traffic congestion by providing 2 x 2 traffic lanes for vehicles connecting the city centre to the southern gateway, i.e. the KL-Seremban Highway.

SMART project won the coveted British Construction Industry International Award in 2008 and received the UN Habitat Scroll of Honour Award in 2011 for its innovative and unique management of stormwater and peak hours traffic.


Pahang – Selangor Raw Water Transfer Tunnel

In June 2009, Malaysia began a project to build the Pahang-Selangor raw water transfer tunnel. It was to be one of the longest and biggest tunnels in Southeast Asia and the sixth biggest in the world - a 44.6 km long by 5.2 m diameter tunnel with a water delivery capacity of 1.89 billion litres per day, laid underneath a mountain range between Pahang and Selangor states.

Pahang-Selangor Interstate Raw Water Transfer Tunnel

This huge tunnelling project was successfully completed in February 2014 and was able to overcome various tunnelling challenges (e.g. over 50 m high empty cavern inside the mountain range, pressurised spring water that shot out as much as 24.6 tonnes per minute, rock burst, etc.) thanks to the strong solidarity of its multinational team consisting of over 1,000 workforce from 15 countries.


Mass Rapid Transit (Line 1 & 2), SBK Line & SSP Line

Klang Valley MRT Lines

The Klang Valley Mass Rapid Transit (KVMRT) Project involves the construction of a rail-based public transport network, Mass Rapid Transit (MRT) system, together with an existing urban rail network, will form the backbone of the public transport system in the Greater Kuala Lumpur/ Klang Valley region. The first MRT line implemented is the 51 km Sungai Buloh-Kajang Line (SBK Line). Construction of the line began on 8 July 2011 and was fully operational in July 2017. The MRT SSP Line is the second MRT line under construction. The line will serve a corridor with a population density of around 2 million people stretching from Sungai Buloh to Putrajaya. The SSP alignment is 52.2 km of which, 13.5 km is underground. A total of 37 stations, with 11 of them underground.

The successful completion of the KVMRT SBK Line tunnels in Malaysia marks an important step in the use of Steel Fibre Reinforced Concrete (SFRC) tunnel segmental lining in Southeast Asia. The valuable experiences gained would encourage other rail developers and contractors in the region to embark on the usage of SFRC tunnel lining for other suitable projects. It is to note that the circle lines KVMRT project is now being planned.


TRX Station and TBM Machines


Ulu Jerai Hydroelectric Project – Underground Powerhouse

The Ulu Jelai Hydroelectric Power (HEP) Scheme was initiated by Tenaga Nasional Board (TNB), Malaysia to provide additional 326 Gigawatt hours (GWhr) power generation due to the increase in electricity demand and to improve in its reliability. The HEP Scheme is located in Cameron Highlands, Pahang State, West Malaysia and comprises of water transfer tunnels from Lemoi and Telom rivers into a 0.74 million m3 capacity reservoir retained by the Susu Dam spanning the Bertam River Valley. The Ulu Jelai HEP Scheme commenced construction in early 2011 for a Contract sum of MYR 820 milllion (US$ 185 million) and is due for completion by early 2017.

The project involves the construction of an underground plant, which will house two Francis turbines with a power output of 191 MW each and the construction of approximately 26 km of hydraulic tunnels, of which, approximately 15 km excavated with Tunnel Boring Machines (TBM) and the remaining using traditional method.

Other underground structures include headrace and tailrace tunnels, surge shaft, two pen stocks, transformer and surge chamber caverns. Construction of the water transfer tunnels were performed using a 3m diameter TBM. Drill and blast excavation technique was employed for the construction of the underground power house, transformer and surge chamber caverns, headrace and tailrace tunnels and penstocks. The surge shaft was excavated using the raised boring technique.

Ulu Jerai HEP Underground Powerhouse


Bukit Berapit Rail Tunnel

Bukit Berapit Rail Tunnel

Bukit Berapit Rail Tunnel, a 3300m twin tunnel is the longest rail tunnel in Malaysia. It is located in Bukit Berapit near Bukit Gantang, Perak, Malaysia. It was included as a part of the Ipoh-Padang Besar Electrified Double Tracking Project. The tunnel was constructed as an alternative to the old winding tracks with many tunnels. The completion of this tunnel saw the closure of the Bukit Berapit Halt.

Construction of the tunnel started in 2008 and was completed in 2013. And now, it has been commissioned and is in operation.


Pantai 2 STP Green Transformation

The country’s first and biggest sewage treatment plant (STP) as well as the largest in Asia Pacific, Pantai 2 Sewage Treatment Plant (P2STP), is constructed underground and equipped with state-of-the-art green technologies. The plant could cater to the growing population until year 2035. Once completed, the plant will be able to receive sewage flow from the 6,700 ha Pantai catchment covering central and south-western parts of Kuala Lumpur.

A 1.423 million PE sludge management facility will be constructed to treat and manage the waste biological sludge, with the provision of biogas power generation facility. The P2STP features various green technologies including utilising skylight concept for the underground plant, effluent reuse, rainwater harvesting and the use of biogas and solar panels to generate electricity. The plant also uses energy-efficient equipment to reduce the amount of electricity consumed.

One of the main highlights of P2STP is the development of  a leisure park with sports, recreational, administration building and community facilities for the local residents above it.


Underground Sewage Treatment Plant (Pantai 2 STP)


Upcoming Tunneling Projects

Mass Rapid Transit (Line 3), Circle Line

The Klang Valley MRT Line 3 Circle Line is a proposed new urban metro railway in Kuala Lumpur, Malaysia. The line is approximately 30 km plus long of which majority is expected to be tunnels and underground stations providing several interchanges with the existing rail networks, including MRT Line 1 & Line 2, KLJ Line, APG Line, KTM and HSR.

Mass Rapid Transit (Line 3), Circle Line


Penang Undersea Tunnel

The Penang Undersea Tunnel is a 6.5km long tunnel which will connect Butterworth, Seberang Perai in the east to George Town, Penang island in the west. When completed, it will become the first undersea tunnel in Malaysia and the second in the Southeast Asia. There will be a toll plaza in the undersea tunnel. With a cost of RM6.3 billion, the tunnel will be the largest privately funded public works project in Penang.

Penang Undersea Tunnel


The Kuala Lumpur-Singapore High Speed Rail

The High-Speed Rail (HSR) is an alternative railway line between Kuala Lumpur and Singapore. It is seen to be in line with the transformation of the nation as it links two urban cities to meet growing demand, catalysing economic growth and enhancing long-term economic competitiveness while improving the quality of life of its people. The HSR will connect 6 cities in Malaysia to Singapore, following a coastal route. The stations that have currently been identified are the terminal stations in Kuala Lumpur (at Bandar Malaysia), Putrajaya, Seremban, Ayer Keroh, Muar, Batu Pahat, Iskandar Puteri and the final one in Singapore (at Jurong East).

On the rapid transit system, it is likely that a bridge or an undersea tunnel will be built between the two countries. If the undersea tunnel was chosen for the project, then there would also be a choice of it being either a sunken tunnel or a bore tunnel. The undersea tunnel was the more favourable option as it would cause minimal disruption to traffic movements during the construction period, as the project would be located nearby the Customs, Immigration and Quarantine (CIQ) complexes of Malaysia and Singapore. However, the decision will be made jointly by the governments of both countries later.



East Coast Rail Link Tunnel

Infrastructure development is critical to the growing East Coast Economic Region (ECER) and rail is a key enabler for the region that can connect economic centres including industrial areas and provide a link to the Greater Kuala Lumpur/ Klang Valley region efficiently. The new alignment of 640km East Coast Rail Line (ECRL) project runs through Kelantan, Terengganu, Pahang, Negeri Sembilan, Selangor and Putrajaya has been identified as a high impact infrastructure project that will form the backbone of ECER’s multimodal transport infrastructure. It will connect smaller towns such as Mentakab and Kuantan in Pahang, Dungun in Terengganu and Tumpat in Kelantan and aims at unlocking the economic potential of these towns as well as uplifting the livelihood of the people who live along the rail line. This will complement existing road/expressway infrastructure such as the Lebuhraya Pantai Timur and the existing KTMB East Coast Line and ports.

The ECRL is a totally new line based on double-track standard gauge design and tentatively starting from Serendah connecting the current rail track of KTM West Coast Line to Bentong and Mentakab and certainly will involve tunnelling thorugh the Titiwangsa mountain range. The current 70km Petronas single railway track, i.e. Kerteh-Kuantan Port Railway Line proposed for Petronas oil refinery logistic infrastructure will be linked and upgraded into this project.