India, Sept. 14 -- The train carrying Boris Johnson, Carl Bildt, and a group of European security advisers had just crossed the Yahodyn border checkpoint into Poland when the drone arrived.

Minutes later, a Russian Shahed drone struck the locomotive still waiting on the platform behind them, destroying the engine and setting a nearby petrol station on fire. A third train, carrying former CIA Director David Petraeus, was at Yahodyn station when the attack occurred.

No one was killed. But the narrow gap between catastrophe and coincidence-measured in minutes and shaped by a scheduling decision-has become the central question surrounding Russia's campaign on Ukraine's western front.

Ukraine's state railway operator, Ukrzaliznytsia, said ...