Indeed, it is this philosophy of cross-sectoral co-operation that saw open source software gain traction in the IT sector initially. The open source premiseThe basic philosophy underpinning open source software is simply that by sharing work freely, development can be accelerated, challenges tackled collectively and innovation fostered more rapidly. Impediments to open sourceYet open source is not in itself a radically new innovation — indeed, it has long had its advocates in the rail sector. Göbel notes that 97% of all software globally has an open source component within it, and now DB is starting to share its application layer in open source format ‘which we have never done before’. Open source and DACFor the open source revolution to succeed, though, it will need to influence major programmes in a tangible fashion.