It may be available through a closet store or a shop that carries library ladders.

Agree with comment above (thanks). Unfortunately, final interior selections like the ladder, etc. were finalized during the interior design phase of the project. Sorry I couldn't be more helpful.

Vandykes.com carries library ladder hardware.

https://www.vandykes.com/rolling-library-ladder/c/1647/?gclid=Cj0KCQjwwY-LBhD6ARIsACvT72NL18eyKnYb8hus2qBTStQmkCXp6lYm6dnRib7jwih8LDcR_hUDUB8aAn6sEALw_wcB

Thank you for the great source! Love it!

This is the company we purchased the library ladder from - https://www.indexd.com/mwe-sliding-ladders