Abstract: A trackbed liner which has a particular utility in a railway trackbed, as well as in other trackbeds such as tram trackbeds. The trackbed liner may include an upper support layer; a lower support layer; and at least one middle filtration layer of a material having a plurality of pores and which is normally impermeable to liquid water. In use and under the load of a vehicle acting on the trackbed, the filtration layer permits passage of liquid water upwardly therethrough but restricts the passage of solids materials, so as to restrict pumping erosion of material located beneath the liner. The trackbed liner may be used to renovate a trackbed comprising ballast contaminated with clay particles. The method includes removing contaminated ballast; laying the trackbed liner; and locating fresh ballast on an upper surface of the liner to provide a renovated trackbed.

Abstract: The invention relates to a trackbed liner which has a particular utility in a railway trackbed, as well as in other trackbeds such as tram trackbeds. The trackbed liner may include an upper support layer; a lower support layer; and at least one middle filtration layer of a material having a plurality of pores and which is normally impermeable to liquid water. In use and under the load of a vehicle acting on the trackbed, the filtration layer permits passage of liquid water upwardly therethrough but restricts the passage of solids materials, so as to restrict pumping erosion of material located beneath the liner. The trackbed liner may be used to renovate a trackbed comprising ballast contaminated with clay particles. The method includes removing contaminated ballast; laying the trackbed liner; and locating fresh ballast on an upper surface of the liner to provide a renovated trackbed.