Le développement des appareils de voie sur plancher en béton à la SNCF

Whereas modern track is generally built on concrete sleepers, until now points and crossings have usually been laid on a wooden surface. Today, thanks to advances in technology, state-of-the-art track is entirely on concrete, thereby putting an end to the discontinuities created as a result of differences in sleeper spacing due to ageing, differences in sleeper thickness and the need for anchoring spades for welded crossings assembled on wooden sleepers.The surface consists of pre-stressed concrete monoblock supports covering the requirements of all turnouts between 0.11 and 0.0154, which means that there are 3,200 definitions of supports. However, a new design had to be developed for points and crossing laid on concrete slabs.Experience has already been acquired in France in use of this type of switches since more than 1,200 crossings have been installed on concrete sleepers. Users are pleased with results since, despite the relatively high cost of these sleepers, they provide good value for money and show excellent behaviour under levelling and lining.