The Bottom Dumper (BD) is suitable for pellets, rock and other easily unloaded commodities and is designed for high-capacity continuous bottom discharge.

Fast loading and unloading are key features of the BD wagon, which is an 8-axle wagon made up of a master wagon and a slave wagon. The bottom of the wagon consists of two large hatches that open entirely during discharge. Emphasis has been placed on the angle of repose, to optimise the centre of gravity and achieve a complete emptying. The wagon is designed for rolling discharge and has a discharge capacity of up to 20,000 tonnes per hour.

The solution and its components are tested and proven in a demanding subarctic climate; the BD wagon is currently in traffic in the Arctic regions of Sweden and Norway. The BD unloading station is a low-cost solution designed to provide a reliable service in temperatures ranging from −40 to +60 °C.

Construction and materials

The construction is a remarkable combination of robust bottom door function and low tare, based on more than 100 years of experience in rail ore transport and steel refinement. By using ultra high-strength hot-rolled steel with a lowest yield point of 650 MPa in the body we have minimised the tare weight and developed a more efficient and environmentally friendly ore transport. The wagon body is built like a boat hull where a supporting frame distributes the forces downward from the load to the chassis. Advanced techniques, such as laser hybrid welding and laser cutting, have been used in the manufacturing process to produce durable seams and minimise the heat effects on the steel.

Maintenance concept

The Bottom Dumper has a modular design which means that damaged parts can be quickly replaced. A goal of our maintenance concept is that two people should be able to exchange any of the wagon components within two hours, with exception for the chassis.

BD in brief



Average Annual Wagon Speed (AAWS) is a key performance indicator of modern wagon fleets. Our BD built for LKAB moves at 17.5 km/h and our new-generation BD for Rana Gruber at 25.7 km/h. Download our AAWS sheet to compare our numbers with those of your own fleet.

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Wagon Specifications BD 20/8 BD 25/8 BD 25/10 BD 30/12
Max axle load 20 tonnes 25 tonnes 25 tonnes 30 tonnes
Line load 8 tonnes 8 tonnes 10 tonnes 12 tonnes
Number of axles 4 4 4 4
Wagon length 10,000 mm 12,500 mm 10,000 mm 10,000 mm
Gauge 1,435 mm 1,435 mm 1,435 mm 1,435 mm
Tare weight 20 tonnes 21 tonnes 20 tonnes 20 tonnes
Leading volume 50 m3 60 m3 50 m3 50 m3
Length between bogie centres 6,444 mm 8,944 mm 6,444 mm 6,444 mm
Wheel base 1,778 mm 1,778 mm 1,778 mm 1,778 mm
Coupler height 1,040 mm 1,040 mm 1,040 mm 1,040 mm
Temperature inverval -40 to +60 °C -40 to +60 °C -40 to +60 °C -40 to +60 °C
Unloading capacity 12,000 tonnes/h 16,000 tonnes/h 16,000 tonnes/h 20,000 tonnes/h
All wagon types can be customised to fit your logistics preconditions. Such as axle loads, length, volume, loading profile, AAR, TSI, etc.


Kiruna Wagon has since 2005 delivered more than 1,000 units of Bottom Dumpers to Swedish iron ore producer LKAB. Bottom Dumper Fammoorr050 transports iron ore from the LKAB Kiruna Mine in Sweden to the Port of Narvik in Norway.

Kiruna Wagon has delivered 40 Bottom Dumpers to Norwegian mining company Rana Gruber AS. Bottom Dumper NO-RG Fanoo, built for a 30-tonne axle load, is a further development of Fammoorr050 and designed to deliver lower tare weight and higher payload advantage.