RAIL SUPPORT SOLUTIONS

Undersleeper Pads

Installation of Undersleeper Pad

Tiflex Undersleeper Pads are a very cost effective means of reducing ground borne noise & vibration in ballasted track systems. Lower vibration transmission not only reduces the risk of damage to supporting and adjacent structures and alleviates noise pollution, but it also minimises the attrition of the ballast itself contributing to track maintenance cost savings.

Tiflex Undersleeper pads are generally more efficient than baseplated track at reducing vibration because there are no fixed anchoring points. The rigid sleeper assembly allows greater track deflection without compromising track stability. Tiflex pads typically provide 12dB reduction in vibration transmission in the 63Hz band.

Tiflex Undersleeper Pads normally consist of a very high efficiency cellular layer which is attached to the underside of the sleepers and is protected from damage caused by the ballast stones, by means of a tough, ballast protection layer of material. The properties of the resilient layer are designed specifically to suit the type of traffic using the track.

Undersleeper pads can be of various designs

• a) normal sleeper pad
• b) partially booted sleeper pad assembly
• c) fully booted sleeper pad assembly
• d) micro pads

The normal sleeper pad covers the whole of the base of a monoblock sleeper. The pad is fixed to the sleeper by the use of epoxy resins. Alternative adhesives such as moisture curing type are available for achieving good bonds with wet sleepers.

The partially booted sleeper pad assembly has a thermoplastic tray, which contains a Trackelast pad to the underside of the sleeper. The arrangement can be designed to prevent any direct contact between the vertical surfaces and the ballast.

Micro pads consist of small tough pads, which are grouted into the assembly during the production process for the manufacture of concrete sleepers.

Undersleeper pads can be retro fitted to existing ballasted track construction, allowing trackauthorities to respond to environmental problems with minimum cost and disruptions to traffic flow.

Tiflex have been developing specialist materials for noise and vibration reduction in twin block sleeper systems used on slab tracks in tunnels and on viaducts and bridges.

Various grades of Trackelast, cork /microcellular natural rubber composite, and microLAST, microcellular rubber grades have been used in proprietary systems around the world where higher levels of insertion loss are required for 25-50Hz bands. 

For higher frequency ranges up to 250Hz, Tiflex have been working with leading systems providers, to develop thick composite pads for areas of critical specifications in order to meet environmental and operating licences imposed by governments and urban authorities. These are designed for high-speed lines and metro operations.

Undersleeper pads are also used as attrition pads. In certain locations Tiflex ballast mats are very useful for reducing damage to track ballast when it is laid on concrete foundations. Special materials have been developed to reduce ballast attrition and these can be supplied pre-cut for rapid installation.

Undersleeper Pads will be manufactured with a protection layer which will either be FC85, FC101 or a geotextile layer.

Sleeper boots and insert pads

Undersleeper Technical Data

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Information in this document and otherwise supplied to users is based on our general experiences and is given in good faith but, because of particular factors which are outside our knowledge and control and affect the use of products, no warranty is given or implied with respect to such information.

Specifications are subject to change without notice. Safe handling data sheet for these materials are available as as PDF downloads. Click here to download