Doomtrain from Final Fantasy VIII. Because it's so ridiculous to run over your enemies with a grimacing eldritch locomotive.

(I am not remotely a train nerd IRL, so I don't have a real train answer)

infinity train

King of the Mountains, and the locomotive class which had an entire region nicknamed after it. The New Zealand Railways class Kb. https://super8.absturztau.be/watch?v=FMz3wcIW2bE

the one with a comfy ride, that is not delayed

A lego one

Soul Train

60163 Tornado if steam, otherwise the Class 68.

The Trans Europe Express that that one Kraftwerk song was about

Certainly not Thomas