The small room next to the wheel contains the sump pump. Thank in advance.
Did you try to remove it?
Backwater valve, turns off the main drain flow (to prevent sewer back flow).
I did not touch it.
So if the basement starts to flood, turn the wheel ???
Shuts it off to prevent sewer from backing up into the home.
In a back-flow event, turning the gate valve will completely close off the flow (in both directions), so it’s used in emergency situations. Some also have a flapper based valve that operate as a check-valve for unattended operated.
I see, ok , Thanks guys. Good night
Exactly what I think it does, too. 
Good one Simon.
Its a gate valve. Typically/usually shut off valve for municipal pipes.
I see them in 1950’s home. The municipality is a lower than neighbouring municipality.
Left to dive…right to rise.
The periscope is just out of the frame.
I love this biz. In 22 years, I’ve never seen that.
so it’s not for steering the house then ?
That;s kool John. I’ve never seen that either in the trades or in inspections. If you get more info please share it!
Thanks everyone for the information. I hope I never have to steer the house in the right direction.
Home build in 1952