Like I mentioned above, Italo is usually cheaper than Trenitalia but because the cabins on lower-class tickets aren't the most comfortable, I'll usually consider Italo only for trains that are less than 2 or 3 hours long unless the Comfort ticket class is cheaper than Trenitalia.
Trenord is the company that resulted from a merger between the state-run Trenitalia and a rail company in the Lombardy region. Trenord trains serve primarily destinations in Lombardy – including Milan's Malpensa Airport.
The main railway in Italy is Trenitalia, run by the Italian government. Trenitalia handles the vast majority of passenger train travel in the country, including the high-speed Alta Velocità (AV) trains.
If you plan to take a high speed train in Italy, it may well belong to Trenitalia. Red Arrow (Frecciarossa) trains are the fastest and all passengers benefit from amenities like charging sockets, free WiFi, air conditioning and a food carriage.
Italiarail shows a whole day's trains in the search results and can book up to 20 people at a time. Trenitalia's own website only shows a couple of hours-worth of trains at a time and can only book up to 5 people at a time.
Trenitalia had already sparked controversy with a proposal that passengers in the cheapest class will not be allowed to use restaurant carriages or even venture into the more expensive carriages, prompting charges in the blogosphere and Italian media of promoting an economic apartheid.
Every passenger of Trenitalia can take luggage and suitcases on board the train for free. Trenitalia luggage policy is not strict about the number of suitcases and dimensions limit, and it doesn't require any fee or extra fee in case of overweight or oversize luggage.
Often there is little difference in the ticket prices between the two. But even more often, TheTrainline offers discounted train tickets months in advance before the national train company itself ( Trenitalia, for example) has them up for sale on its own website.
Trenitalia Domestic trains are non-smoking, air conditioned and have power outlets at seats. Most day trains have a lounge/cafe car. Train Types: Frecciarossa trains run on high speed lines with exclusive WiFi, online entertainment portal and 4 classes of service.
Some trains require seat reservations, and on other trains it's optional. If you're riding a train on which reservations are only recommended or completely optional and you don't have a reservation, you can sit in any available seat in the appropriate class you have booked.
FIRST CLASS TRAVELExecutive class - 1x1 leather seating, up to 10 passengers per car, armchairs with reclining backrests and leg-rest extensions, a snack with water or tea is included. Food and drinks may be purchased in the Restaurant Car. This class provides access to Business Lounges on the stations.
Regionale Veloce (RV) are the semi-fast train services in Italy on which many different types of train are used, on routes they share with the slower Regionale, these RV services are faster because they skip more stations.
There is typically one bathroom per train car on Italian trains. On newer trains, and especially high-speed trains, they are more spacious than what you might find on an airplane and offer the same basic features as those of a plane lavatory - a flushable toilet, sink with running water, soap, and paper towels.