Thanks to the massive success of mobile access devices such as netbooks or Apple’s iPhone 3G, Internet on the move has become one of the prominent features of today’s information society. With the emergence of wireless and mobile communication networks, the railroad industry is now catching up on this new technology in their battle with low-cost operators to bring more productivity and entertainment possibilities to its passengers. With millions of daily commuters as potential service users, this transport branch offers high business opportunities. However, while most field trials and research effort have mainly focused on the enabling technology, little research effort has been conducted to forecast the demand-side. This article tries to fill this gap by presenting original results gathered from a large-scale survey amongst 1324 regular train travellers. By means of the Product Specific Adoption Potential method, we predict the potential market penetration of wireless Internet services onboard trains and estimate the size and nature of five adopter segments in terms of socio-demographics, drivers and thresholds, willingness to pay, applications and quality of service. We will discuss the practical implications of these insights in order to develop viable business models, set up introduction strategies and build out user-driven infrastructure networks.