Sika Deutschland GmbH has been the key supplier of the German Railways for a range of coatings, sealants and adhesives for more than 100 years. The flexible grouts of the Icosit® KC 300 range have won worldwide renown for tailor made, long lasting direct fixation of rails to solid substrates, i.e. concrete and steel. They are incorporated in a variety of trackwork designs, in discrete and continuous fixation, embedded/floating rail, lawn track, for railway, light rail, tram and crane track installations.

Sika provides design and technical assistance to consultants, operators and contractors for optimum and innovative trackwork solutions under a wide variety of conditions of exposure, for wheel loads ranging from 4 to 75 metric tons.


These load-bearing, flexible polyurethane grouts of the Icosit® KC 330/Icosit® KC 340 range fulfil 4 main requirements for direct fixation:

  • Levelling out inevitable tolerances between rail and concrete or steel substrate
  • Highly efficient electrical insulation for prevention of stray current leakage as a safeguarding against signalling malfunction, electrochemical corrosion and data transfer interference
  • Resilient intermediate layer for optimum reduction of noise and vibration transmission, i.e. vibration damping, cast-in-situ after alignment to eliminate any point loads
  • Powerful adhesive for added safety and maximum performance


Successful dynamic performance tests with minimum 3 to 4 million cycles are a prerequisite for market introduction. Field tests with the German Railways proved that during 28 years of exposure to dynamic stress and weathering, with virtually no maintenance, the reduction in flexibility of the Icosit® KC 330 flexible grout was only marginal. The University of Calgary confirmed suitability for service temperatures from -40°C (-40°F) to +70°C (+158°F). Field test reports confirm reduction of structure borne sound transmission of up to 18 dbA. The high performance is also governed by the fact that these flexible grouts – contrary to pure elastomers – are all somewhat compressible which is absolutely essential to compensate for the unfavourable shape factor in practice and to retard the "bouncing back" effect.

In Erfurt, Germany continuous undersealing of rails with Icosit® KC 340 reduced vibration by 40%.
In 1986, the baseplates of the lawn track in Fellbach, Germany were supported by Icosit® KC 330, resulting in an extremely quiet and aesthetically attractive system.
The baseplates of the crossover of the Heathrow Express in London were undersealed with Icosit® KC 330 in situ for maximum precision and riding comfort.
In Memphis, Tennessee, the very basic suspension of heritage trolleys necessitated maximum vibration absorption through an embedded rail design with Icosit® KC 330.
In Tuen Mun, Hongkong, the light rail vehicles have run on vibration-absorbing Icosit® KC 330 since 1987.

Discrete fixation – Regardless of the type and size of the baseplates, the pourable or injectable flexible grouts can be adopted to all situations of direct fixation, particularly for special trackwork, in tunnels and on bridges, with or without sleepers/ties/gauge bars, under certain circumstances even without anchor bolts.

Floating rail (Embedded rail) – Various options are mainly based on designs with a recess (trough) in the concrete which may be produced with a slipform paver. The rail is then suspended in the trough and cast-in-situ all aroud with Icosit® KC 340 without any mechanical fixation. Other alternatives use a flat concrete slab with prefabricated sound-dampening filler blocks attached to the web of the rail and the flexible Icosit® KC 340 grout cast around the foot of the rail only.

Lawn track – Lawn track designs are becoming very popular as they are aesthetically and ecologically attractive. Various design options include embedded rail, discrete fixation with baseplates and specially adapted concrete sleepers/concrete ties on continuous, slipform-cast concrete beams with Icosit® KC 340 as vibration-reducing intermediate layer cast-in-situ after alignment of the track.


Whether you are involved in the design, construction or maintenance of railway tracks, light rail tracks or heavy crane tracks, Sika can assist you with its long-term experience with field-tested Icosit® KC 330/340 resilient grouts for a multitude of design variations with optimum cost/performance relation.