Measurement of railhead longitudinal profiles. A comparison of different techniques

The underlying principles are considered plus attractions and limitations on the practical application of three different types of longitudinal rail profile measuring equipment which can be used in a vehicle. Axlebox accelerometer systems are a good compromise for obtaining statistical profile data at line speeds. Other accelerometer-based systems are the best means of obtaining data at a few metres per second but are corrupted by extraneous vibration. Both these and chord-based systems are compromises in most practical circumstances where there is significant extraneous vibration.