Train Day was the quasi-holiday on which Marielda's Crosstown Express train went on its first trip.
“
Now, now, can't have you crying. Not on Train Day.”
Though another train, running along the outskirts of the city, had existed for a year prior to this (perhaps having even had its own Train Day), the original train was mostly used to carry freight, with few passengers. As such, the departure of an additional train from a newly built station at the meeting point of Orchid, Chrysanthemum, and Helianthus Parish was a major public event.
Maelgwyn's Faithful was holding an event for their more affluent members on the train's ballroom car.
Train Day has also become a nickname for the day (usually Thursday) of a new Friends at the Table episode's release.