Eurail Confusion

I suggested easyJet or Vueling and left off Ryanair because it flies into Bergamo which is an outlying airport. However, you'll do fine so long as you follow the rules. Ryanair's fees for not staying within baggage weight and size limits are worse than most budget airlines. Do not miss the check-in deadline. If you don't have a boarding pass in hand when that deadline arrives, your ticket will be worthless and you'll have to buy a new one at full price for a later flight. (This is true for all budget airlines, not just Ryanair.)

when I check the Eurail website I can't find any trace of this train. You definitely are confused. Eurail only packages and markets rail passes. They do not list any trains on their website. You must be looking at RailEurope, which lists some trains, but not nearly all, usually the more expensive ones, and marks them up over the European counter price. And, according to the Bahn schedule, that train only runs Thursdays and most Tuesdays, never on Saturdays, in June.

The Barcelona Franca-Milano Centrale night train does NOT run on Saturdays. It runs Tuesday-Thursday-Sunday. However, while it appears on both the German Rail and Swiss Rail timetables for 12 June and 26 June, for reasons unknown to me it doesn't appear for 19 June. You might want to consider flying a budget airline like easyJet or Vueling between Barcelona and Milan. The reason you are having trouble finding complete timetables for Milano-Monterosso is that new timetables will go into effect throughout most of Europe on 12 June and Trenitalia is notorious for being the last national rail company to upload theirs to their website. Put in a date for the same day of the week you wish to travel that is earlier than 12 June and you'll see all the possibilities.

Am on a train from Venice to Milan to Monterroso on June 16 and have got my confirmation and tickets thru Rail Europe

Is it possible Eurail doesn't list the train you want because it is sold out? Not sure but one possibility.

To confirm what Tim posted, Renfe (the Spanish site) shows this train, Trenhotel 11273 from Barcelona to Milan, on Tuesday, June 21, but none on June 18, 19, or 20. It is pretty expensive---192,10 euro for a bed in an all-women compartment. No promo prices are left. they also have seats and first-class compartments available.

Thanks for all the feedback! I ended up finding a very cheap flight via Ryanair for that day.

you have no hope.