Railways

RAILWAY TUNNEL STRUCTURES

Rail traffic causes tremors that are transmitted into adjacent inhabited buildings or industrial structures requiring protection. People perceive these vibrations as an annoyance. Underground railway lines also generate structure-borne noise and secondary air-borne noise. Elastic decoupling of the track bed structure from the tunnel floor is an effective vibration-isolating method. It is used to minimise vibration and airborne sound immissions and reduce track and subsurface stress loads and damage.
 
Using elastic components not only reduces forces and pressures but also wheel wear with lower requirements. Track elasticity increases and the stress loads on the track bed structure, supporting structure and subsurface are reduced. This helps to minimise vibrations and significantly increases ride comfort.
 
Options for elastic decoupling in tunnel structures comprise the installation of a mass-spring system or a sub-ballast mat in the case of ballastless tracks or elastic rail bearings with suitable rail pads or base plate pads in the case of ballasted tracks.

 
 

BRIDGE STRUCTURES

When trains travel over railway bridges, there is considerable vibration and noise pollution due to vibrations and structure-borne noise transmitted into the subsurface via the track. As a result, separate measures must be taken to reduce vibrations and structure-borne noise on bridges, especially in conurbations and cities, also due to statutory requirements regarding vibration and airborne noise control.
 
An elastic bearing, with sub-ballast mats, for example, helps significantly minimise the vibrations transmitted from the tracks to the bridge’s supporting structure and thus also reduces structure-borne noise. Bearings can also prevent potential destabilisation of the ballast bed and the track position. This reduces acoustic emissions into the environment, especially in the case of steel bridges. Moreover, the elastic bearing also protects the bridge structure itself from possible damage caused by vibration transfer into the supporting structure and also ensures a structural seal.