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Ballasted track & light mass-spring systems

Ballast and mass-spring system with Calenberg sub-ballast and track mats

Sub-ballast and track mats are proven elastomer products made from natural or synthetic rubber. Sub-ballast mats are used to reduce the oscillations and vibrations from rail traffic or modify the stiffness of the track superstructure. They also prevent excessive wear of the track ballast.

Sub-ballast mats are available in various designs and stiffnesses for axle loads up to 250 kN and train speeds up to 300 km/h. In principle, there are two types of sub-ballast mat, which differ in their construction and composition.

The granulate mat

Sub-ballast mats in rubber granulate have a wear-resistant protective coating of rubber on both sides.

This protective coating allows the mats to resist mechanical loads e.g. from ballast or from being run on by light construction machinery, without the isolating layer (granulate layer) being damaged.

With the aim of reducing vibrations in neighbourhoods affected by railway lines, Calenberg Ingenieure has developed sub-ballast mats (USM) with a special shape that exploits the outstanding properties of rubber to their full effect:

The conical stud mat

This sub-ballast mat consists of three functional layers combined in one component. The conical studs are made from natural rubber, which behaves as a spring with an optimum ratio of static to dynamic stiffness. The back forms the supporting layer for the studs and the composite component performs as a damping and protective layer that withstands the loads from the ballast bed just as it does when forming the solid substrate supporting the steel reinforcement cages in the construction of slab track. The two reinforcing textile fabrics incorporated into the back provide the necessary robustness and make the composite component resistant to undesirable strains and damage. The mats have an overlapping strip on their longitudinal edge to allow effective butt jointing during placement on site. With the product available in series USM® 1000 to USM® 4000, Calenberg can provide the optimum protective solution for all types of track superstructure. They offer the most suitable solution for every task from ballast protection in the case of reduced ballast bed thickness to efficient isolation of structure-borne sound and vibrations in mass-spring systems. The mats can be designed and manufactured to suit specific vibrational requirements. Whether the mats are used in the form of point, linear or full surface bearings depends on the circumstances and objectives in each case. The user can expect the highest level of operational reliability as a result of Calenberg's decades of experience in the design, production and project-specific application of its products. The results of laboratory tests in accordance with internationally recognised standards prove that the product will continue to function properly for the useful life of the track.

Dynamic effectiveness of conical studs

The shape of the conical studs is no accident. It is a visual expression of the engineering design, which optimises the good properties of the rubber for the application. The cone deforms under load into the shape of a hemisphere, a shape which achieves an almost constant natural frequency for the range of loads found in all commonly encountered applications. For the user, this means that the protective effect not only occurs for the design load case but also for different loading conditions arising from rail vehicles, without any loss of functionality. The conical studs are designed for a variety of load ranges to ensure that they are effective over the specific frequency range of each application profile.

Use of conical stud mats

It is generally accepted among industry professionals that sub-ballast mats or elastic bearings (point, linear or full-surface bearings) under track slabs in mass-spring systems provide an effective means of protection against structure-borne sound and vibrations. All other uses of elastic elements in track superstructures are known to be less effective in protecting against vibrations.

Superstructure drainage

The conical stud mats are solid not hollow, and contain no voids into which water could penetrate, unlike foamed products. Silt from abrasion of the ballast or sediment from the soils, e.g. surrounding a tunnel, forms deposits around the conical studs. The pumping action required for the drainage function to work is caused by the behaviour of the studs under dynamic loads and displaces the deposits laterally. The shape of the studs creates the space required for the process to function properly. The stud shape is useful in another respect. The voids between the studs also allow drainage in the longitudinal and transverse directions so that water, which cannot be prevented from penetrating the track construction, can be reliably conducted in a controlled way to the drainage outlets.

Advantages of conical studs

Volume-compressible materials made from foams or fibres lack the anti-vibrational effect because of their inherent void content. If water gets into these voids, the inertia of the water counteracts the effective isolation of the vibrations from rail vehicles. High hydrostatic pressures are created in the material because water is incompressible.
Longer-term loads such as a stationary train compress the rubber. However, the memory effect of the vulcanisation grid "remembers" the original shape and forces the rubber to recover from its deformed shape after unloading.
Compression set is a measure of any remaining deformation. The compression set of the conical studs is so small that their dynamic effectiveness is not adversely affected in the long-term.
Volume-compressible materials used in this area undergo lasting deformation because their structure changes under load.
The same creep behaviour can be observed in rubber, but it takes place only under very high compressive stresses applied over long periods.

Calenberg Ingenieure designs, manufactures and markets elastomeric sliding bearings, and statically or dynamically loaded structural bearings (elastomeric bearings) for buildings and structures, sub-ballast mats and trackbed mats for track construction as well as other elastomer-based products for noise insulation and environmental protection.

USM® 1000-W

The side of the profiled USM® track mat facing the ballast or concrete slab has a fabric-reinforced rubber covering layer that is resistant to abrasion, oil, ozone and the weather.


Calenberg Ingenieure designs, manufactures and markets elastomeric sliding bearings, and statically or dynamically loaded structural bearings (elastomeric bearings) for buildings and structures, sub-ballast mats and trackbed mats for track construction as well as other elastomer-based products for noise insulation and environmental protection.

USM® 2020

The side of the profiled USM® track mat facing the ballast or concrete slab has a fabric-reinforced rubber covering layer that is resistant to abrasion, oil, ozone and the weather.


Calenberg Ingenieure designs, manufactures and markets elastomeric sliding bearings, and statically or dynamically loaded structural bearings (elastomeric bearings) for buildings and structures, sub-ballast mats and trackbed mats for track construction as well as other elastomer-based products for noise insulation and environmental protection.

USM® 2025

The side of the profiled USM® track mat facing the ballast or concrete slab has a fabric-reinforced rubber covering layer that is resistant to abrasion, oil, ozone and the weather.


Calenberg Ingenieure designs, manufactures and markets elastomeric sliding bearings, and statically or dynamically loaded structural bearings (elastomeric bearings) for buildings and structures, sub-ballast mats and trackbed mats for track construction as well as other elastomer-based products for noise insulation and environmental protection.

USM® 2030

The side of the profiled USM® track mat facing the ballast or concrete slab has a fabric-reinforced rubber covering layer that is resistant to abrasion, oil, ozone and the weather.


Calenberg Ingenieure designs, manufactures and markets elastomeric sliding bearings, and statically or dynamically loaded structural bearings (elastomeric bearings) for buildings and structures, sub-ballast mats and trackbed mats for track construction as well as other elastomer-based products for noise insulation and environmental protection.

USM® 3000

The side of the profiled USM® track mat facing the ballast or concrete slab has a fabric-reinforced rubber covering layer that is resistant to abrasion, oil, ozone and the weather.


Calenberg Ingenieure designs, manufactures and markets elastomeric sliding bearings, and statically or dynamically loaded structural bearings (elastomeric bearings) for buildings and structures, sub-ballast mats and trackbed mats for track construction as well as other elastomer-based products for noise insulation and environmental protection.

USM® 4010

The side of the profiled USM® 4010 track mat facing the ballast or concrete slab has a fabric-reinforced rubber covering layer that is resistant to abrasion, oil, ozone and the weather.


Calenberg Ingenieure designs, manufactures and markets elastomeric sliding bearings, and statically or dynamically loaded structural bearings (elastomeric bearings) for buildings and structures, sub-ballast mats and trackbed mats for track construction as well as other elastomer-based products for noise insulation and environmental protection.

USM® 4015

The side of the profiled USM® 4015 track mat facing the ballast or concrete slab has a fabric-reinforced rubber covering layer that is resistant to abrasion, oil, ozone and the weather.


Calenberg Ingenieure designs, manufactures and markets elastomeric sliding bearings, and statically or dynamically loaded structural bearings (elastomeric bearings) for buildings and structures, sub-ballast mats and trackbed mats for track construction as well as other elastomer-based products for noise insulation and environmental protection.

USM® G-1015

The G-series of the USM® track mats have on the surface that faces either the ballast or the concrete slab a fabric reinforced chloroprene layer which is abrasion, oil, ozone and weather resistant.


Calenberg Ingenieure designs, manufactures and markets elastomeric sliding bearings, and statically or dynamically loaded structural bearings (elastomeric bearings) for buildings and structures, sub-ballast mats and trackbed mats for track construction as well as other elastomer-based products for noise insulation and environmental protection.

USM® G-1023

The G-series of the USM® track mats have on the surface that faces either the ballast or the concrete slab a fabric reinforced chloroprene layer which is abrasion, oil, ozone and weather resistant.


Calenberg Ingenieure designs, manufactures and markets elastomeric sliding bearings, and statically or dynamically loaded structural bearings (elastomeric bearings) for buildings and structures, sub-ballast mats and trackbed mats for track construction as well as other elastomer-based products for noise insulation and environmental protection.

USM® G-1027

G-series USM® track mats have a fibre-reinforced chloroprene covering layer on the side facing the ballast or the concrete support slab. The chloroprene layer is resistant to abrasion, oil, ozone and the weather.


Calenberg Ingenieure designs, manufactures and markets elastomeric sliding bearings, and statically or dynamically loaded structural bearings (elastomeric bearings) for buildings and structures, sub-ballast mats and trackbed mats for track construction as well as other elastomer-based products for noise insulation and environmental protection.

USM® G-1032

G-series USM® track mats have a fibre-reinforced chloroprene covering layer on the side facing the ballast or the concrete support slab. The chloroprene layer is resistant to abrasion, oil, ozone and the weather.


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Trade fairs and exhibitions 2017

ICCX Russia 2017

05. - 08.

December


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