International Public Partnerships Limited (INPP) announced that it has made an additional investment of EUR 10 million (US$ 12.24 million) and made a contingent commitment of a further EUR 14 million (US$ 17.14 million) to the 100% indirectly owned special purpose company that owns the Northern Diabolo Rail Link. Diabolo is a rail infrastructure investment that integrates Brussels airport with Belgium’s national rail network.