At Easter, 2017, significant engineering works at and around Bath Spa Station will result in disruption (TPOD / Temporary Period od Disruption) - known as TPOD3.
From
Wessex Railway WalksTemporary Period of Disruption - Bath Spa station is due to be clossed for a period of 3 (three) weeks in April 2017- again further details to follow - this will affect the walking season in 2017 - again details to follow - Provisonal dates are Sunday 9th April 2017 to Sun 23rd April 2017
Much more detail next month (November 2016) ... but early indications are that there will be considerable bus operations rather than trains in and around Bath, and I would expect the TransWilts to be rather busy with diversions.