Drawing on some 30 years’ experience, the DFF ADH system is suitable for slab tracks of all types and concrete sleepers.
The Bonded DFF ADH fastening system has 2 solutions available. A standard model for plain line tracks and customised models for turnout applications.
Its deployment significantly reduces vibrations from passing trains and mitigates against the development of some types of corrugation.
The one piece bonded system comprises a top and bottom plate factory assembled by bonding using vulcanised rubber. This provides a number of unique features:
The DFF ADH System can be constructed by either top down method or bottom up construction and is adaptable to all types of slab.
Vibration isolation can be provided in a range of stiffnesses down to 10.5 kN/mm although a typical standard stiffness configuration would be around 25 kN/mm. The bonded resilience provides longitudinal, vertical and lateral stiffness.
As the resilience is above the baseplate the stresses to the anchorage are reduced allowing economical designs with 2 anchor points. Different anchor configurations are available utilising plastic dowel or cast inserts subject to operational requirements. We can assist with design considerations for aspects of the anchor design. The use of anchor inserts and drop down bolts eliminates the need to lift the rail over anchor studs when replacing the baseplates.
The DFF ADH system can be provided in various lengths to suit turnout applications. The application of bonded DFF ADH baseplates in turnouts has been long established as an ideal method of introducing resilience into turn out applications, providing the resilience on the surface of the slab where it can be maintained.
The DFF ADH System is suitable for use on LRT/Metro applications. The key advantages for this type of application are the very high level of electrical resistance, long electrical leakage path and the lateral resilience which can minimise corrugation propagation. The DFF ADH System can be constructed by either top down method or bottom up construction and is adaptable to all types of slab.
The Pandrol DFF ADH System is ideal for use on bridges for attenuation of vibrations and for replacement of existing rail fastening systems where bridges are being refurbished. The complete factory assembled baseplate in the DFF ADH System provides the opportunity to attach the system directly to the bridge superstructure or to the timber, concrete or steel bearer and provide a high level of adjustment to suit.
Depending on the type of rail clip used on the DFF ADH system, structure interaction between the rail and the structure can be managed by low toe load and/or zero longitudinal restraint (ZLR) fastening options. Depending on the length and type of bridge, there may be opportunities to use ZLR fastenings throughout or through parts of the bridge and avoid the use of rail expansion joints. Where rail expansion joints are installed the ZLR fastening can be used to separate the location of the rail expansion joint and the structural expansion joint avoiding the maintenance risk of those 2 features being at the same location.
The Pandrol DFF ADH system is suitable for Main Line (Passenger Freight) applications typically CEN CAT C according to EN 13481-5:2012. It is ideally suited to construction techniques that benefit from large amounts of adjustment for example, where a bottom up construction method is used. The DFF ADH system can be installed in many different configurations and anchor arrangements, it is best to contact us for specific application requirements where we can provide the necessary guidance on which Pandrol DFF ADH application would most suit your project. The system is adjustable laterally and vertically, typically +/- 12 mm laterally per rail seat and + 30 mm vertically. If your project requires additional adjustment please contact us.