If the railing is round, you can easiely get it by making a brush:
Make it half as long as the diameter of the pit.
Then turn it into a Cylinder and press the V-Key (for vector manipulation):
Then move the three right (at least in my pictures) points to the exact middle of the next side of the pit. Allign the three middle-vectors so they are exactly so that the both lines have a 90° arc:
Now you hava a hand-railing that exactly matches the one of the tube.
Hope you understood it, possibly more due to the pics (I'm really tired, so my spelling is almost completely gone), but anyway- if it helps
If for some reason I have switched my language to german or other things, just mail me Tigris@durahcell.de
or contact me over ICQ UIN: 47835030
Hopefully I'm a bit more awake by then