QUO VADIS? COMPETITION BETWEEN BOLTED,SCREWED CLAMP & DRIVEN SELF-TENSIONING CLIP RAIL FASTENENINGS By F.A Wingler, October 2021

The technical paper deals with the two principal categories of ELASTIC Rail FASTENING or RAIL FIXATION SYSTEMS, which we find on railways around the globe:

  1. Bolted or screwed Clamp Systems, where the Clamping or Down-Hold Force is generated by tensioning a Clamp through applying a torque on a quenching screw bolt; so-called “Threaded Clamp Systems”.
  2. Screw-less self-tensioning driven Clip Systems, where the described Clamping or Down-Hold Force is generated by Deflection, when the Clip gets deflected through driving it in a cast-in shoulder, housing or anchor insert; so-called “Screw-less Non-Threaded Self-tensioning Clip Systems”.

To the Group A belong the French RN and Nabla Fastening, the Japanese Shinkansen 120 Fastening (Kowa) and Spring-Steel-Leaf Fastening, the Pandrol SD Fastening, and the German evolution of the Epsilon shaped Tension Clamps from Vossloh developed at the Technical University of Munich under Prof. Hermann Meier (HM Clamps; Germany), produced by Vossloh, Schwihag (Germany Switzerland, USA), Voest Alpine (Austria), Pandrol, Agico (China) and by some other Chinese Rail fastener suppliers, and some Steel-Spring Leaf Fasteners developed in the former UDSSR.

To the Group B belong the Brands of the Pandrol PR and “e” Series Clips, the Fast-Clips, the Indian RDSO Pandrol modifications of the Mark I to VI Series Clips and Logwell G Clips, the Deenik Style long range Clips trading with a wider deflection range (developed in the 1950-tees in Netherlands) under the Brands “SAFELOK”, further developed my Ralph McKay, (Austria) – now Pandrol, Voest Alpine and Progress Rail –  and the Ukraine KPP 5 Clip/Vossloh SB V 4 VK Fastening.

In answer to reports on fractures of SKl 15 Tension clamp fastenings on monolithic Rheda 2000 non-ballasted tracks, Vossloh has modified the spatial bend of its SKl 15 Clamp. The new SKL 15 HF tension clamp has a significantly higher natural frequency, which means that it has an increased vertical fatigue limit.

Worldwide the Pandrol Fast-Clip is superseding the self-tensioning Pandrol PR and “e” Series Clips on ballasted tracks.  On non-ballasted tracks for High-Speed Rail the screw-tensioned SKl Clamps dominate over the self-tensioning Clips.

To learn more about the spectrum of advanced rail-fastenings, download the PDF:Quo Vadis