The subject matter of the invention is a mass damper for railway applications.

Rail dampers are damping elements mounted on a rail (the rail neck or foot, sometimes the bottom part of the rail head) with a bonding or by means of additional elastic fasteners. Rail dampers are usually distributed in equal intervals along a rail, in sections between the points of fastening of the rail. The typical structure of a rail damper is a core, in the form of a metal or steel insert (or inserts), coated with an elastic synthetic material. The effectiveness of a rail damper depends on, inter alia, the type of fastening, type of elastomer, shape and material of which the insert is made.

The Polish patent PL 212951 describes a running rail equipped with an acoustic damper. The damper, made of a synthetic material and particles of an iron alloy, covers the rail neck on both sides and is bonded to the rail. Made in the process of extrusion or injection, the damping element completely fills the chamber between the bottom surface of the rail head and the top surface of the rail foot. It is made of a thermoplastic material containing finely ground and dispersed metal particles in an amount ensuring that the density of the damping element is higher than 2.4 g/cm ³ .

The German patent DE4000992 describes rails clad on both sides with synthetic rubber dampers to reduce vibrations. Spring clamps press the dampers against the body of the rail. A narrow slit between the rail head and the damper is filled with a thick patching paste, and the damper has a smaller thickness in this area. An additional spring clamp presses the damper against the rail foot.

The American patent US11174597B2 specifies a clip assembly for securing first and second tuned mass dampers to respective first and second sides of a rail. The clip assembly includes a bar element having a connector portion extending between first and second ends thereof and formed to be positioned in a predetermined location relative to the rail at least partially under a foot of the rail, and a first clamping arm connected with the connector portion at the first end of the connector portion, the first clamping arm being formed to engage the first tuned mass damper. The bar element also includes a linkage section located at the second end of the connector portion. The clip assembly includes a second clamping arm extending between upper and lower ends thereof, the lower end comprising a locking portion securable to the linkage section, and the upper end being formed for engagement with the second tuned mass damper.

SUBSTITUTE SHEET (RULE 26) The present invention is an easily-mounted rail mass damper which reduces noise generated by movement of trains and propagated in the vicinity of railways by reducing the vibration amplitude, including, without limitation, within the high-frequency range.

A rail mass dumper containing a resonating element, made of steel, embedded in an elastic sheath, with a substantially L-shaped, elastic, profiled fastener, is characterised by the sheath is made of elastomers; a metal plate with a hollow is adjacent to one of the sides of the sheath, whereas a vertical arm of the fastener has its first curve set in the hollow of the metal plate; the second curve, substantially U-shaped, corresponding to the shape of the rail foot, is in the lower part of the vertical arm of the fastener; the horizontal arm of the fastener has a substantially I J- shaped bend at its end, suitable for placing it over the rail foot.

Preferably, the damper’s sheath is made of elastomers made from recycled, granulated waste tyre rubber.

Preferably, the hollow in the metal plate is in its upper part.

Preferably, the shape of the hollow in the metal plate corresponds to the curve in the vertical arm of the fastener.

The rail mass dampers are mounted symmetrically, in pairs, on both sides of the rail, in the space between the rail foot and the rail head, and pressed with elastic fasteners of a dedicated shape. The damper adjoins the rail neck on its entire surface, filling in the fishplate space. The metal plate adjoining one of the sides of the elastic sheath protects its surface against deformation caused by the pressure put by the elastic fastener. The plate is shaped in such a way that a hollow, preferably in the upper part of the plate, serves as a lock for the elastic fastener. The U-shaped curves reach below the rail foot, pressing the damper against the rail. The damping mass, elastically fastened to the rail, is excited to vibrate by moving rail vehicles, and owing to the elastic rubber layer, vibrations are shifted in phase relative to the vibrations of the rail. The elastic rubber layer performs preliminary damping, whereas the core, made of a stiff material, such as, e.g., steel, has dimensions which ensure that its resonance frequency is within the vibration frequency range of the rail. The sheath can be made of granulate of various parameters; stiffness of the sheath depends on the type of granulate used.

An advantage of the rail mass damper according to the invention is the effect of damping the acoustic wave emitted by the rail, including, without limitation, by the narrowest, vertical part of the rail, i.e., the rail neck. Laboratory experiments have shown that the rail mass damper according to the invention can help reduce the vibration level by 2-4 dB more compared to

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SUBSTITUTE SHEET (RULE 26) standard solutions. Moreover, the rubber-based elastomer does not lose its structural continuity when stretched or pressed, and once free of load, returns to its original shape, as well as elongates significantly when stretched. The rail mass damper executed according to the invention is easy and quick to mount, so no long stoppages of rail traffic are required.

The figures show an example version of the subject of the invention. Figure 1 shows the rail mass damper without the fastener, Figure 2 shows the fastener of the rail mass damper, while Figure 3 shows the method of fastening the rail mass damper on the rail.

In the version shown in the figures, the rail mass damper comprises an elastic, elastomer sheath 1 with a steel resonating element 2 embedded permanently along its entire length, and elastic, substantially L-shaped fasteners 5. The damper surface opposite the rail is equipped with a profiled metal plate 3 with a hollow 4 in its upper part, where the elastic fasteners 5 are locked. The elastic fasteners 5 are in the shape of metal plates substantially L-shaped. The vertical arms of the fasteners have their first curve 6 in a shape 5 corresponding to the hollow 4 in the metal plate 3, set in the hollow 4 of the metal plate 3. Another curve 7, in the lower part of the vertical arms, is substantially U-sh ped and corresponds to the shape of the rail foot. The horizontal arms of the fasteners 5 have a substantially U-shaped bend 8 at the end, to be locked on the rail foot.

Rail mass dampers are mounted symmetrically, in pairs, on both sides of the rail, in the space between the rail foot and its head, and tightened with specially shaped elastic fasteners alternately on both sides of the rail. The fasteners are locked on a hollow profile of the metal plate and the rail foot, pressing the dampers against the rail neck. The entire surface of the damper tightly fills in the rail fishplate space.

The sheath of the damper in this version is made of elastomers made from recycled, granulated waste tyre rubber.

SUBSTITUTE SHEET (RULE 26)