The American cops took the slower, cheaper train from Kyiv to Donetsk. 

After repeatedly traveling between Ukraine and the United States, there were more comfortable ways to make this final, 400-mile journey. But the five FBI agents felt like luxury tourists compared to most travelers onboard. They could afford spacious private rooms while locals were sleeping 10 to a cabin. The train moved haltingly, past empty country and villages that, to the Americans at least, looked as if they’d been frozen in the Cold War.