I think this is a terrible example for flat earth talking point. I would focus on the earth being stationary and nobody being able to prove curvature which are easy to verify.
The issue with this example with smoke from a train versus the volcano; is that any globe proponent will tell you that the earth is spinning and the smoke from the volcano exits at the same rate of motion with the earth (therefore it stays in place).
The train has smoke trailing behind it because it has accelerated over and above the rate of speed that the earth turns out, therefore smoke trails behind.