[Does so]

I would see the nose of the train first—coming or going.

I used “generational” to infer the eventual advent of square-riggers that would carry topgallant, royal- and sky-sails.

Columbus probably already knew of the earth’s roundness from personal experience at the masthead. He and his crew would see an approaching ship’s masthead before seeing the deck, as stated previously.

[Does so]

Credit due centurion316.

[philman_36]

He and his crew would see an approaching ship’s masthead before seeing the deck, as stated previously.

As would any human, but such an observation would be due to the limitations of the human eye and perspective, not from curvature.
As is evidenced by videos up thread, a stronger zooming instrument would have allowed them to see the deck.