I've searched the messages and don't find an answer to the following issues. Your help is appreciated!

I read at one of the sites recommended here that ES* trains have a restaurant/bar car positioned between the first class and second class cars. However, when I look at schedules I'm considering at lunch time, only one of the schedules at Trinitalia indicates that food is available. Any explanation?

One of the trains I'm considering is an EC. However, I don't find any explanation of the meaning of EC. Is that an Espresso train? If so, I'm leery because the site mentioned above indicates that Espresso trains can be uncomfortable.

Thanks again for any help you can offer.

EC means Euro City.

Perhaps the following will help.

Intercity-Express (ICE)
Intercity/Eurocity (IC/EC)
Interregio (IR)
Interregio-Express (IRE)
Regional-Express (RE)
Regionalbahn (RB)
Night trains (NZ, EN, D-Zug, UEX, CNL)
International trains: Thalys, Eurostar

IR and IRE are German mostly and stop frequently.

As for Trentalia, who knows.
I have not found it reliable.

Get on board with your own food if any doubt.
I do.

Eurocity (EC) trains are fast international trains. The type of catering available will vary according to the nationality of the train. A Eurocity train travelling in Italy may have started its journey in Germany and might have a German restaurant car.
Tell us which journey you're making and someone might know more about the trains on this specific route.

Thanks, Bob and Geoff!

The EC train I'm referring to is on July 13 as follows:

EC #126 Cisalpino Lemano
Departs Milano Centrale 16:25
Arrives Stresa 17:26

Considering that it's only one hour, I'm not overly concerned so long as I have a seat reservation. But I'd still like to know if it should be avoided and if I should instead choose an IR train that is available at a different time.

Just because a train doesn't have a bar/café car doesn't mean there won't bve food. They often have a guy who goes through the cars wheeling a cart with the same stuff you'd buy at the café car.

But it's not very appealing stuff anyway, so your best bet is to take food onto the train with you. In every train station there are plenty of places to pick up san dwiches, salads, drinks, etc. It's cheaper than on the train, too.

Is a 20-minute layover in Milano Centrale long enough to make a connection for two healthy athletes with luggage who have never been to that train station? Trenatalia schedules it that way, but I have to ask if that's reasonable.

Cisalpino trains are modern tilting trains of the same basic design as Italian Eurostar trains. Train 126 goes from Milano to Genève. It should be a lot more comfortable than an IR train, but IR trains have the advantage that you don't need to reserve seats (reservations are, I think, only possible in first class). For a one-hour journey, I wouldn't bother trying to get a meal.

If you have 20 minutes, you are in luck. Usually the connection times are shorter. I have made them when they were under 10 minutes.

There is no restaurant car on this particular train, but there is a bar where usually sandwiches or something similar are available.

Please Note. Reservations on this train are obligatory. That is the case with just about every Cisalpino I have ridden on.

Thank you to everyone for your help. Much appreciated!

Word of advice: don't eat the train food! It's not poisonous, but it's very overpriced and almost anything you bring on board will taste better.

A second word of advice: some of that "food" you buy in the train stations can be just as "unappealing" as the stuff they roll down the aisles.

Choose wisely.

We bought some gnocchi Alfredo in Roma train station for dinner on our overnight train to Paris. It was very good.