We went to Germany and England and we were very fortunate with the help of this group to avoid high costs of train travel and had minimal issues with transfers. It was recommended to purchase the Bayern card for Germany/Austria (Munich, Fussen, Salzburg, and Regensburg) and when in England (Seven Sisters, Bath, and Windsor) to purchase tickets in advance and avoid busy travel times.
I am now researching Northern Italy ( Milan, Turin and Genoa) and hoping for some advice to save some money on train travel. Thanks!
Regionale trains don't go on sale, but the long distance fast trains through Trenitalia (state run, more wide reach) and Italo (private company) can be bought for very little if you buy WAY in advance AND are ok with restrictions (of changeability and refundability). If I have a trip that utilizes regionales as well, I wait to buy them all together when they are available (many schedules don't get released until December and/or June) as I don't want to deal with multiple transactions and separate "trips". In general, I have my long distance "home base changing" trips booked in advance for VERY little (I even scored a 2-for-1 first class trip once which was cheaper than two economy tickets in 2nd class) and then buy the regionale trains (which are CHEAP anyways) for my day trips on that day.
You can book fast trains in advance at discounted prices- read the restrictions
Regional trains do not need to be booked in advance as price never changes and they can’t sell out
There isn’t really a pass that is beneficial in Italy
Use the official website or their easy to use apps
Trenitalia- fast and regional trains
https://www.trenitalia.com/en.html
ItaloTreno fast trains only in certain routes
https://www.italotreno.com/en
Train travel in Italy info
https://www.seat61.com/train-travel-in-italy.htm