Mapping technological development using patent citation trees: an analysis of bogie technology

We create a generational patent citation tree to reveal the development of bogie technology in the high-speed rail industry. We cull the information in patent citations to reveal the generational development of bogie technology by analysing patent titles, patent publication dates and patent-granting regions. We then measure the development of bogie technology by calculating its technological development on-orbit rate and by mapping the stages of technological development and its regional diffusion. The results show that bogie technologies are in a period of sustained growth and this period of sustained growth will remain. Technological development is accelerating and this acceleration will persist, although the global dispersion of technology lags behind in scope and speed.