Reliable and cost-effective new development of sliding steps in trains

Knorr-Bremse GmbH, Division IFE, headquartered in Kematen/Ybbs, Austria, is a leading developer and manufacturer of electrically powered boarding systems for rail vehicles. The company sets standards for sliding and swivelling sliding doors for trams, underground trains, suburban trains, regional transport, high-speed trains and passenger coaches. Johann Wilflinger, Group Manager System Development trade show, was faced with the challenge of developing a new, technologically advanced boarding system for rail vehicles.

The new development not only had to be more reliable, but also significantly more cost-effective than the previous model. This was achieved by dispensing with the cost-intensive step mat and a modified drive concept that replaces belt drives. This reduced the weight, the number of components and the clearance height of the sliding step. A simplified guide system was also intended to prevent jamming or a heavy gait.

Another aim was to reduce life cycle costs by designing the boarding aid to be as maintenance-free as possible. No operating fluids such as oils or greases were to be used in order to minimise maintenance costs. The sliding steps had to function perfectly at all times despite large temperature fluctuations and a wide range of soiling.

Several innovative measures were implemented in the new development of the entry-level system in order to increase reliability and reduce costs. A decisive element of this solution is the new drive concept, which consists of a dryspin® high helix lead screw made of stainless steel and a lead screw nut made of iglidur® J through a central spindle drive. This combination offers a higher service life and efficiency, as the specially developed high-performance polymers from igus® are wear-resistant.

The dryspin® high helix lead screw and the associated Flanschgewindemutter aus iglidur® J ensure virtually wear-free operation and high efficiency. This improved running performance is achieved in particular by the asymmetrical geometry between the spindle and lead screw nut. In addition, the spindle holds in any position, even with heavy kicks and sweeping movements and, in the event of a power failure, the spindle can be operated by hand. With the help of special sliding blocks, the forces are absorbed when the spindle is extended, while the plain bearing bushes made of iglidur® G in the locking system ensure a reliable and maintenance-free function. These components are insensitive to dust, dirt, moisture and cleaning chemicals.

Overall, by using the igus® products, Knorr-Bremse GmbH has developed a robust and cost-effective solution that meets the requirements of modern rail transport. The new sliding steps are not only more reliable and cost-effective, but also easier and simpler to install and maintain.