The UN’s Food and Agriculture Organization says 25 MMT of exportable grain are stuck in Ukraine and threatening global food security. Canadian Prime Minister Justin Trudeau says his government will work to help Ukraine export this grain, but the logistical hurdles are daunting. The first shipment of Ukrainian grain exited the Romanian port of Constant last week, but rail on the Romanian side of the border is too limited in capacity. Plus, Constanta authorities will give preference for their limited capacity to Romanian origin exports.  Rail lines into western Europe are of a different gauge, forcing costly and time-consuming transfers. In a similar vein, grain exporting Ukraine into Poland for export out of Latvia’s three...