The route from Vadodara is given below:
Note that a narrow gauge line existed from Vishvamitri (VS) in the past. The section between VS to Dabhoi was converted to broad gauge some years ago. The less important narrow gauge branch to Chandod was later converted but did not seem to have any BG passenger service until now.
More recently, with the advent of the Statue of Unity it was decided to extend the broad gauge line a further 32 km to the dam township called Kevadiya Colony. This station was finally called Kevadiya. Electrification was also expedited from Dabhoi.
Here you can get the list of trains serving Kevadiya:
There has been some talk of this line (and indeed) the Statue of Unity being an unnecessary expenditure which may not be of much use to the nation. There are various arguments for and against this.
The long-distance trains will provide additional connectivity from some cities (especially Chennai) towards Surat and Vadodara where there may be a need for more capacity. And additional services from Ahmedabad and Mumbai towards these cities.
The Jan Shatabdi between Ahmedabad to Kevadiya will include Vistadome coaches, for what they are worth.