Fast, High Speed, Bullet Train from Naples or Salerno to Venice

take a look on the DB site, the best place to look up trains in Europe. It's at https://www.bahn.com/en You'll want to use the Italian names Napoli and Venezia, and look for a day later this month. I see 1-2 trains per hour

If you haven't found it on the Trentitalia site one possibility is you are looking at a date too far in the future. Same thing will happen on the DB site

The Man in Seat 61 has some tips on the high speed train options:
https://www.seat61.com/trains-and-routes/frecciarossa.htm

Note: it looks like Venice to Naples requires a change.

The term “bullet train” refers to the fastest trains operated by Italy’s two train companies with the term used interchangeably for Trenitalia’s “Frecciarosa”trains and Italotreno’s “Italo” trains. Both travel up to 186 mph. NTV is a private Italian train company that operates Italotreno which has “ bullet trains” running from Salerno to Rome’s Termini and Tiburtina stations in 2 hours 7 minutes. Trenitalia, Italy’s national train company, also runs fast trains on that route. Italotreno’s fastest trains on the Naples to Rome route take 1 hour 13 minutes. But it’s Trenitalia’s Frecciarosa trains running from Napoli Centrale station to Roma Tiburtina station that are the fastest, taking as little as 57 minutes.
From Rome to Venice, Italotreno runs trains in 3 hours 49 minutes. Here again, it’s Trenitalia that has the fastest trains which run from Roma Tiburtina station to Venezia in as little as 3 hours 7 minutes. Both Trenitalia and Italotreno trains use Venice’s Mestre and Santa Lucia train stations. Tickets for Trenitalia trains should be booked at www.Trenitalia.it for the best fares. Other sites, such as www.TheTrainline.com, book Trenitalia and Italotreno train tickets at slightly higher prices so they can make a profit.
Italotreno’s train tickets can be booked at www.Italotreno.it

the term "bullet train" isn't really used in Italy so if you are searching for that term that might account for why you can't find it. It has been applied to the Shinkansen high speed trains of Japan, and now has sometimes been used by some people to describe fast trains.

The Freccia trains operated by Trenitalia translate as "arrow" and then a colour - Frecciarossa (red arrow), Frecciargento (silver arrow) and Frecciabianca (white arrow) - in decreasing order of speed.

The trains run by Italo, which I prefer, are just called Italo. They even have a coach with a movie theater.

When you are using the online schedules, just use the one word Salerno. Rome is either Roma Termini (the main station) or Roma Tiburtina. Venice has two stations - Venezia Mestre (the station on the mainland and you don't want that, and don't be tempted to hop off) and Venezia Santa Lucia (named for the saint for whom the church next door is named, the station on the islands, the end of the line and the one you want - be prepared for a magnificent view as you look over to the Grand Canal).

Naples is Napoli Centrale.

So you want Salerno (or Napoli Centrale) to Venezia Santa Lucia (sometimes abbreviated on displays in the station as Venezia SL.

Just using a random date, I am seeing direct (no changes) Trenitalia trains from Napoli Centrale to Venezia S. Lucia. While they have no changes, they will have brief stops along the way. Journey takes abt. 5.5 hours (it's a long way). There are also a VERY few directs from Salerno, and only one that I'm seeing that takes abt. the same amount of time.

There are several Italo trains doing the Napoli Centrale> Venezia S Lucia run per day with no changes: They take roughly the same amount of time as the Trenitalia trains: 5.5 hours. Only 1 direct train (at least on the random date I'm looking at) from Salerno, taking 6 hours, 17minutes.

Like Nigel said, I've never heard the term "bullet" applied to Italian trains, just specific ones in Japan.

If you're looking at dates after 12 Dec, all the schedules might not be loaded yet.

I took the Frecciarossa train from Venezia St. Lucia to Firenze, and a few days later took the Frecciarossa from Firenze to Salerno. Neither of those had a train transfer, but they both had a couple of brief stops. The second one stopped for passengers at two Rome and two Napoli stations.

Thanks for the info, everyone, on the Italian trains.
It’s incredible that today you can get from Salerno to Venice in 5.5 hours — all the more reason to ditch the planes and take the trains.
There is a difference between what speeds the trains have attained during testing and what speeds they’re permitted to run on the tracks with passengers.

While Trenitalia’s Frecciarosa trains run up to 186 mph on their routes, in 2016 a Frecciarosa hit 245 mph during a test run. The fastest working trains in the world remains the Maglev trains in China that run from Shanghai’s airport into the city with a top speed of 286 mph.

The Japanese Shinkansen “bullet trains” now can run at top speeds between 200-275 mph. The country’s LO Series Maglev train has hit 374 mph during test runs. Beginning in 2027, there will be Japanese Maglev trains running between Tokyo and Nagoya at top speeds of 314 mph.
While Spain’s AVE trains usually top out at 193 mph, it’s S-102 Talgo and S-103 Velaro trains hit top speeds of 217 mph on their runs between Madrid and Barcelona. It was a Velaro S-103 that hit 251 mph in 2006 and established the Spanish rail speed record.

French TGV passenger trains can run up to 199 mph. In 2007 a modified TGV Alstom V-150 set the world record in a test run when it hit 357 mph.
The big surprise is that Morocco bought TGV technology and, for the past four years, has had its “ Al Boraq” train running 200 miles between Casablanca and Tangier at speeds up to 199 mph. If that train was around at the time the movie “Casablanca” was filmed,
there may have been no need for Humphrey Bogart, Ingrid Bergman and Paul Henreid to argue over those letters of transit to get out of Casablanca. Instead, they could have simply taken the train.