It is often times relatively hard to find reliable information about bus, ferry or train schedules in Siberia. Search through a few websites and they all give you different departure times. Even Russian railways official site isn’t always trustworthy.
Schedules keep constantly changing, so I give you just an idea for your planning: this is
how the ferries were running (information given from the port) between Listvyanka and Port Baikal October 5th, anno domini 2017.
This is the ferry you’ll need to take from Listvyanka if you are hopping on Circum Baikal railway.
Thus finding the schedules of the historical train are a totally different story that I can’t unfortunately help you with. Neither are the locals.
– There should be a steam train leaving 14.40 on Thursdays from Listvyanka, but others tell that from Listvyanka trains run only at night (leaving around 2 am) meaning that you wouldn’t enjoy much of the scenery. So the best way to do it, is to walk to a train station and ask. This goes with any routes.