Staircase on poop deck

[Christophe Puttemans]

Hello guys,
On the Titanic deck plans available on this site, I noticed there was a staircase on the poop deck, right below the bridge.

It apparently leads to a room below where the steering engines and gear are located.

I was hoping someone could show or tell me how this staircase looked like. I have never heard about it before because it was apparently not on the Olympic. How did they prevent Third Class passengers from accidentally going down there?

 

[Ioannis Georgiou]

The staircase was enclosed, the door could be locked.
Olympic had the same.

 

[Ioannis Georgiou]

Here is the door on Olympic leading to the staircase from a negative in my collection (haven't come to scan it yet so only this poor quality pic).