Embedding compounds for rail

General information

Rails for trams must be laid precisely to the millimeter both as regards direction and depth. Traffic noise also needs to be kept as low as possible, especially in residential areas, or if necessary reduced. Using an embedding material meets these requirements. As a rule the rails are laid out exactly in their horizontal and vertical positions and placed on set screws or other supports, which in turn rest on the underlying surface. This surface is generally concrete. The space between the concrete surface and the foot of the rail is then filled with the embedding material, which in this process serves as both as a leveling and a noise and vibration reducing layer. According to the VDV (Verband Deutscher Verkehrsunternehmer, Association of German Transportation Companies) Information Sheet 6201 "Rail Embedding," three different types of material are used for embedding:

- Cement-based embedding material
This material does not reduce vibration and its long-term performance is no better than moderate. As it also has no electrical insulation properties and cannot be installed while rail traffic is running, this type of material is used relatively rarely.

- Bitumen-based embedding material (more information here)

- Synthetic-based embedding compound (more information here)