Ah - but the critical people are those who would use the bus / train but can’t / don’t because it only runs for part of the year.The use of school days / school holidays is already often used by public transport operators, it’s a very common differential used by bus companies.
Buses are the most heavily used form of public transport in UK so if their users can cope I’m sure so can rail users.
It’s all very well to add some holiday extras (which this basically is) but to expect people to memorise University term dates to know whether their bus runs every 20 minutes or every 75 is not the way to encourage them to ditch their cars on a permanent basis.