St. James for service in English, the Duomo for mass in Gregorian chant
Ciao Alice and welcome to our DT forum!
I assume you are interested in church services in English?
St. James Church is the American Episcopal church in Florence, you can learn more about it here:
http://stjames.it/
It is really close to the train station, just a few blocks away on Via Rucellai 9.
As reported on the site, the Sunday service schedule is:
9:00 a.m. Holy Eucharist with sermon and
11:00 a.m. Holy Eucharist with sermon and music
If you would like to try something different, I recommend attending
mass in Latin and
Gregorian chant at the
Duomo (Florence's cathedral), the service is at 10.30 a.m. You can see further mass times on the site:
http://www.duomofirenze.it/index-eng.htm (if not indicated, they will be in Italian).
The Cathedral is also just a few blocks from the train station, so both are viable options to reach on foot from the station. I suppose it also all depends at what time your train arrives into Florence.
Hope you enjoy your visit to Florence!