Learning by exporting: The impact of the China–Europe Railway Express on city-level innovation in China

Engagement in export trade is critical for the cross-border exchange of information and knowledge, which has been identified as the mechanism of the learning-by-exporting effect. However, there remains a dearth of research on the learning-by-exporting effect in conjunction with cargo transportation. This study fills this gap by investigating the knowledge flow promoted by the China–Europe Railway Express (CRE). On the basis of newly assembled city-level patent citation data, we apply the synthetic difference-in-differences approach for identification. The results indicate that the CRE increased the average city-level patent citations of European patents by 5.83%, and this growth originated mainly from the machinery, electronics and automotive sectors. Further heterogeneity analysis of the number of CRE operations demonstrates that such an effect occurs through the role of CRE in increasing the frequency of interactions between Chinese export firms and foreign buyers. Our findings reveal the CRE-related learning-by-exporting effect and contribute new knowledge flow mechanisms to transport–innovation studies.