Measuring the deflection of a sequence of sleepers at a transition zone

Railway track and its support form a system that must maintain line and level under load. Loss of line and level results in increased stress and can lead to greater track geometry degradation and damage to track components. Transition zones are generally designed so that track stiffness changes gradually over some distance rather than suddenly. This paper describes the development of a laser based system which can measure the deflection of a sequence of sleepers at a transition zone. The paper will demonstrate that such a system will enable the efficient measurement of track structural stiffness at a transition zone and can give a rapid assessment of track quality.