Ui is the type designation (special wagon class U).

Suspension bars are load-bearing fixtures that hang the load between the two bogies of a schnabel wagon rather than setting it on a fixed bridge between the bogies (well wagon).


The Uaai 839 is a 32-axle (2 x 16-axle bogies) schnabel wagon with a maximum loading capacity of 454 metric tonnes.

The particular feature of a schnabel wagon is that the two bogies are separate and are only connected by the load itself.

DB (German railways) operates one Uaai 839 for heavy transport.


--------------------------------------------------
Note added at 17 hrs (2013-11-19 23:30:52 GMT)
--------------------------------------------------

Articles on the web often mention lifting arms. This is not entirely correct, the arms suspend the load between the two ends of the wagon (bogies), but are not actively used as lifting gear.

Suspension bars are also known as cradle support beams, suspension beams, side beams and, when a bridge connects the bogies, as schnabel bridges - a bridge may have a load bed or be an open structure.