In this comparative study from New Zealand: https://www.nzta.govt.nz/assets/resources/research/reports/4... you can find a Comparative evaluation of transport modes where maritime shipping is cheaper than train, but this depends on the number of containers (you can put much more on a vessel). If we can increase the number of containers on trains, this could change. Also right now the China-Belgium trip can take 20 days by train (cf. https://www.train-chain.com/) and usually around 30 days by sea.