Project overview

This bus is a glassfibre Bimodal Tram System capable of driving with rubber tyres on roads and also on a track.

The concept was presented with an award by Hyundai Engineering in 2009 for its development progress and results, and the buses performance was further evaluated in test operations during 2010.

It then received another Award, 'The Grand Prize of International Public Design 2010/2011' and test runs were carried out at Gimpo airport in 2012. These were so successful that the bus was subsequently promoted to drive at the expo in Yeosu 2012 and it now drives in Sejong Special Autonomous City which is the second capital city of South Korea, where 9 ministries and 4 national agencies are located.

Banner image courtesy of Nikola Medimorec –


Our solution

The bus has a 50kWh battery system with 620V (12 battery modules with 14 cells per module, 80Ah cells). REAPsystems supplied the Battery Management Electronics (BMS) to Kokam (battery cell manufacturer, South Korea). We were involved with the system integration and carried out the calibration and tuning on-site in Korea. We provided on site support for several days and were part of the initial tests drives at HANKOOK facilities near Busan in South Korea, as as seen in the video.

Key challenges

Although the project comprises of highly innovate technologies, the battery and BMS were considered to be plug and play technologies at the time. It was the first hybrid bus project with such a large battery where regenerative braking was used.

State of charge (SoC) calculation was very difficult because the battery never comes to a full charge or full discharge due to the hybrid operation of the bus. At the same time the energy management of the vehicle uses the SoC to make decisions.

It was a real challenge for us to support the project over such a great distance and through language and cultural barriers, but we do love a challenge!