The notion of constructing a linkage infrastructure between Java and Sumatra Islands across Sunda Strait was initiated and developed during 1960 - 1965 by a team of the Institut Teknologi Bandung. Furthermore, this was followed up by series of preliminary studies and surveys by domestic and international institutions. Nevertheless real measures have never been initiated. The construction of the linkage is urgent, since the existing ferry system will become unmanageable to transport passengers, cargo and goods in the coming decade. The main reason for putting this linkage infrastructure aside has been classically a financial matter. PT Nusantara Tunnel Indonesia intends to propose an integrated system for the linkage infrastructure with regional development in order to ease the financial burden and at the same time raise the relevance of the Nusantara Tunnel initiative.
A report recommends construction of inter-island combination of suspension and ordinary bridge system over Sunda Strait with the total span of about 18 km to cross the 27-km-wide strait. However, without a revolution in material science and construction technology, the construction of the bridge system is far from possible. The investment cost for such a system, according to the report, could be as high as US$ 7.4 ~ 24 billion. Considering the international unit price of suspension bridge of around US$ 1 billion per km, the bridge total cost could run over US$ 18 billion. Another report proposes a concrete submarine tunnel system to float on the surface of the seabed. Even though the investment cost could be as low as US$ 700 million, as the report claims, from the technical point of view the reliability of this system is questionable. To mention only a few potential problems of this system, first, is the structural stability due to dynamic loads from traffic, second, concrete protection technology, and the last is scouring problems on the tunnel foundations.
Herein, an underground tunnel constructed at least 40 meters under the seabed is proposed to link Java and Sumatra Islands. The tunnel is designed to carry electric car trains that move passengers, cars, buses, trucks, trailers and combination trucks. The lesser capital investment and better safety system both for passengers and cargo as well as having virtually no need for a ventilation system when compared to a highway tunnel are among the reasons for the underground tunnel selection. In addition to the electric car train, Nusantara Tunnel will be used to move oil and gas, coal slurry, extra high power transmission, and telecommunication lines so as to make the tunnel multipurpose.
Regional development in the Provinces of Lampung and Banten will also be carried out. A university campus, recreational facilities, rest and resort areas, golf course, entertainment and residential area, terminals and malls will be constructed. Other important facilities such as depots for oil and gas, telecommunication, rolling stock, coal slurry pumping station and switchyard will also be built. The regional development will consider the existing land use and operational facilities. In that way the Nusantara Tunnel system will speed up the regional development and stimulate the economy in both Java and Sumatra Islands to a level never imagined previously. In the long run Nusantara Tunnel system is expected to be an integrated part of an uninterrupted railway system from Beijing in the north to Bali in the south.
The tunnel proposed herein constitutes an interconnected twin tunnel 33 km long that will be constructed in two phases. Each tunnel is of double elliptical shape with an 8.5-meter flat side and a 6.6-meter vertical height carrying two-way single-track electric car train with maximum traffic capacity of 15,500 passenger car units per day. The first phase of the tunnel will cost approximately US$ 1.5~2 billion to construct and US$ 4 million per annum for maintenance, operation, and repair. This will require a toll fee of as much as US$ 20 per passenger car unit to travel one way. The travel time required making a one way trip would be approximately 1 hour.