Class U special wagon
- Bulk goods wagons for transporting powders, etc.
- Dual coupling wagons for joining wagons with different coupling systems
- Well wagons including Schnabel wagons
- Self-discharging hoppers with loading hatches
- Trials vehicles for RoadRailer and Kombirail systems for intermodal transport.
Between 1964 and 1979 bulk goods wagons for liquid and gaseous materials (tank wagons) were included in Class U before being reclassified in 1980 as Class Z.
Bulk goods wagons for transporting powders (powder wagons)
The powder wagon is a special form of bulk goods wagon designed to transport goods in powder form. These wagons are pneumatically unloaded, usually by using compressed air. For goods that might react with oxygen in the compressed air, nitrogen is used instead. These wagons are used for bulk commodities, such as cement, that are so fine-grained they cannot be poured, or at least do not pour very well, and so cannot be emptied under gravity. Under the UIC system they are given the category letter U and index letter c. The do not normally have their own compressors but must be unloaded using external equipment.
The current designation for all well wagons is Ui, which can be supplemented as necessary by the index letters a, aa, k, kk or s. The load limits on low-loading wagons are not indicated by letters. The former German wagon classes were St and SSt.
In 1998 the Deutsche Bahn had a total of 180 well wagons of 43 different types. They are used to move very large and heavy goods that would exceed the loading gauge on flat wagons. Such loads typically include: combine harvesters, generators or narrow gauge vehicles.
The largest low-loading wagons are designed as Schnabel wagons, made from two completely separate sections. Each section rests on multiple-axle bogies or groups of bogies. The two sections each support a beak-shaped carrying arm which, in turn, supports one side of a low-loading platform or is directly fixed to the outsize load to be transported. In the latter case the load becomes temporarily part of the vehicle itself. The wagons have hydraulic equipment with which the load can be raised or lowered in order to manoeuvre it past obstacles. There are about 30 examples of Schnabel wagon in Europe, North America and Asia.
Typical loads for these vehicles are large boilers for power stations, turbine components or power station transformers. Due to their heavy weight and outsize dimensions these goods are not usually transported in normal goods trains, but are moved in special trains and need careful preparation. Whenever transportation restrictions arise with a wagon and its load due to its weight and size, it is designated as an abnormal load and must be labelled in accordance with the RIV as a U type. When the vehicle is unladen the two carrying arms are joined directly to one another; the wagon can then travel in goods trains at normal speeds.
List of selected well wagons
|Class number||Maximum carrying capacity||Wheelsets||Quantity|
(DB as at 31 Dec 1997)
|Uis 632||25 t (24.6 long tons; 27.6 short tons)||2||25|
|Uiks 635||19 t (18.7 long tons; 20.9 short tons)||2||27|
|Uais 732||50 t (49.2 long tons; 55.1 short tons)||4||16|
|Uaai 812||159 t (156 long tons; 175 short tons)||10||1|
|Uaai 820||157 t (155 long tons; 173 short tons)||12||1|
|Uaai 821||190 t (190 long tons; 210 short tons)
(180 t or 180 long tons or 200 short tons
with suspension bars)
|Uaai 823||230 t (230 long tons; 250 short tons)||16||1|
|Uaai 831||275 t (271 long tons; 303 short tons)
(250 t or 250 long tons or 280 short tons
with suspension bars)
|Uaai 836||317 t (312 long tons; 349 short tons)||20||1|
|Uaai 837||398 t (392 long tons; 439 short tons)||24||1|
|Uaai 838||341 t (336 long tons; 376 short tons)
(313 t or 308 long tons or 345 short tons
with suspension bars)
|Uaai 839||454 t (447 long tons; 500 short tons)||32||1|
Hopper wagons with loading hatches
A range of funnel-shaped self-discharging wagons is also classed as special wagons. Their external shape resembles the open hoppers, but they have an enclosed roof with loading hatches or in some other way do not fulfil the criteria for a wagon with opening roof.
Literature and media
- "Bahn TV, Schwerlasttransporte: Riesentrafo auf Reisen; Mai 2008, Video 11 Minuten". Retrieved 2009-02-19.
- Stefan Carstens: Die Güterwagen der DB AG. MIBA, Nürnberg 1998, ISBN 3-86046-030-7