Take a look at "Fence & Stairs Set" object at
www.objectsonline.com
Munual could downloaded for free. Or let me know - I could send this manual to You.
However in this case some details couldn't be also exactly as on the picture.
1) Railing over first tread is curved (not linear)
2) Seem's like all tread cover is also not straight.
Another details could be done quite well
- stringers (positions and height)
- posts&railings could be entered any customs
- general stairs shape