The railway played a large part in late nineteenth century and early twentieth century globalization since, to benefit from the international economy, peripheral countries needed cheap inland transport. This paper discusses how the railway transformed the economy of South Africa’s Cape Colony during the first era of globalization. A very large share of the Colony’s GDP came from rail transport – its resource saving effect was one of the highest in the world at that time. We estimate that 46 to 51% of the Colony’s increase in labor productivity between 1873 and 1905 came directly from the railway, whether from investment in the rail network or from savings in transport costs. We argue that it was the boom in diamond production, necessitating the building of the railway to connect the Kimberley diamond fields with the international economy, that weighted the Colony’s economy so heavily towards the rail transport sector. The railway not only boosted the Colony’s growth, it also re-shaped its economic geography, organizing it around the railway lines that connected the diamond mines with the ports. Areas not served by the railway missed out on the benefits of globalization. As these areas were mostly populated by blacks, the railway helped to create a dual economy with a racial social divide and was later instrumental in creating black ‘homelands’ and establishing the apartheid institutions.