A rotary car dumper
or wagon tippler
(UK) is a mechanism used for unloading certain railroad cars
such as hopper cars
(tipplers, UK). It holds the rail car to a section of track and rotates the track and car together to dump out the contents. Used with gondola cars, it is making open hopper cars obsolete. Because hopper cars require sloped chute
in order to direct the contents to the bottom dump doors (hatches) for unloading, gondola cars
allow cars to be shorter, thus lowering their center of gravity
, while carrying the same gross rail load
Originally, individual cars would be decoupled and placed in the dumper, but now it is possible to dump an entire unit train
of coal without uncoupling any of the cars. The cars used for these trains are equipped with AAR
Type F rotary couplers
on one end, with this end generally indicated with contrasting paint color. The dumper rotates
the cars on the axis
of the couplers.The cars must all oriented the same way, failure to do will result in a broken coupler when the dumper rotates.
Rotary dumping of cars provides a number of advantages and disadvantages:
- Rotary dumping eliminates the need for maintaining the additional components of a traditional hopper car, such as hopper doors and door locks.
- While Hopper cars may be used in rotary service, they are occasionally first converted into Bathtub Gons
- Rotary dump installations are generally associated with faster train unloading times, although this......