Train travel from Siena to Rome in mid September

Siena to Rome for £63 on the train is fine if someone is booking it for you.
But you could cut out the middle man if you feel comfortable using the internet to book yourself.
The bus is actually the quickest way Siena to Rome and a good value https://www.flixbus.com/bus-routes/bus-rome-siena ;
The bus stop is inside the walls on the hill in Siena, the train station is outside the wall and below the hill that Siena sits on. But in the age of COVID if you think you will need to use the toilet during the 2 hour 45 minute bus ride take the train since there is a toilet on every car. This is the site to buy direct with the train operator https://www.trenitalia.com/en.html

I’ve used FlixBus in Italy when it’s more convenient than the train. From Siena, it would be my first choice. They have an easy to use app. The sooner you purchase a ticket, the more money you’ll save. Right now, tickets for mid September are as cheap as $9.99.

I think the quoted train price is high. We also used the Flix bus. My recollection is that it was about 10 euros/person. The advantage to the bus is that it picks you up on the edge of old town. (By the cathedral that has St. Catherine relics) The train is obviously at the train station down the hill from the old town. You might need a taxi or a bus to get to the train station. We were there October of 2019. I do remember booking the bus tickets the night before. We were told they occasionally sell out. The bus goes to Termini in Rome which is where the train would end up as well.

If you do want to take the train it is so easy to purchase tickets for Italian trains.

Just looking at the Trenitalia website, you can buy an all Regionale ticket (one connection in Chiusi) for 17.85 EUR, that is not much slower than connections with a fast Freccia train. You can buy at the station when you are there as the price is always the same, no reserved seats, and there are connections about every hour in the afternoon.

Even a connection with a fast train is 59.50 EUR walk-up price which is a lot less the 63 GBP.

I'd use somewhat the same method as mentioned in the previous reply. Using trains in Italy is easy and Regionales especially are quite inexpensive. If you want to make your own transportation arrangements, you basically have a few choices.....

• Bus (as mentioned earlier)
• Regionale with one change in Chiusi
• Regionale to Florence and then high speed Freccia to Rome

It's not really a huge inconvenience to take a taxi to the bottom of the hill to access the rail station, but of course the choice is yours. You can easily buy tickets at local stations but if you do that, you MUST validate Regionale tickets prior to boarding on the day of travel or risk hefty fines. If you buy tickets online, as I recall they come pre-validated. Also note that tickets for the Freccia trains come with compulsory seat reservations that are specific to train, date and departure time so you can ONLY use the one train listed on the ticket.

be careful which currency you are in so you don't compare apples with oranges.

Your post quotes in UK Pounds. The fares in Italy will be in Euro.

Is the walking tour company British? Are you? If so, do you know about the mandatory quarantine in Italy for us Brits?