1 Ginny: So taking the local train timetables and geography into account, the answer must be the Miracle of the Mad Nun of Foligno.
2 Minnesota Jones: Right! So press the little brass levers marked "mad" and "nun".
2 Monty: I don't believe this...
3 [sound]: Click! Whirrrrr!
3 Ginny: The brass plaque is moving! It's revealing another one!
3 Minnesota Jones: What does it say?
4 Ginny: {reading} "On the way to Rome you meet a Florentine, a Perugian, and a Neapolitan. Florentines always tell the truth, Neapolitans always lie, and Perugians sometimes tell the truth..."

Foligno is south of Florence, and not on the train route between Florence and Venice.

The reason I'm using Foligno here is because of the Miracle of the Mad Nun, which was an event I witnessed in person, in 2001. You can read about it here.

---

2017-09-30 Rerun commentary: Also, the reason I picked a Perugian in the new riddle is that I also visited the town of Perugia on the same trip. In fact, the very day of the Miracle of the Mad Nun, I had begun in Perugia, having spent the previous night there. I had the local strangozzi pasta - a sort of square cross-section spaghetti - with a truffle sauce at a local restaurant, and it was the best meal of three whole weeks spent in Italy. I had planned to go back one day, but alas the restaurant - La Vecchia Perusia - seems to have closed down.