89-km–long route from Slyudyanka-2 to port Baikal is a great opportunity to enjoy the changing views of the lake as the train rides along the shoreline from south to north and back. You will pass through 39 tunnels making several 20 min stops to take a stroll outside.
If you want to travel by yourself you may enjoy two basic variants: southward and northward. Note that official Russian train directions are irrelevant to north-south and are only two: to the west (на запад) and to the east (на восток). This is what you will always see when dealing with railway timetables. So in case of Circum-Baikal Raiway to the west means northward to the port Baikal and to the east means southward to Slyudyanka. The most common starting point is Slyudyanka. Local train that shuttles on the route is called matyanya #951/952.
Summing up the connection timetables it will need another day for the round journey.
It's important that food stores are scarce on the railway, so take something with you or use the bar.