Field Testing and Instrumentation of Railway Vehicles

Experimental investigation on the use of multiple very low-cost inertial-based devices for comfort assessment and rail track monitoring

“…Direct track geometry assessment can be performed using accelerometers installed on axle boxes, applying double integration on the acceleration data acquired, in a simplified approach [3,25] or ideally considering the rail-wheel contact modelling in the transfer function [18,[29][30][31] to estimate irregularities. Accelerometers installed on the bogie and inside the car body are widely used for running behaviour and ride comfort assessment [3,7,32]; at any rate, they also can be used for geometry analysis if the suspension displacements are known [4] or if the dynamic properties and the operating conditions are well known [33,34] and considered in the train-track dynamic model. To meet the data quality requirements, the use of tactical, industrial or navigation-grade inertial sensors (medium/high-cost) in such systems is preferred.…”

“…When displaced away from this bogie, the influence of the other bogies increases, and the signal presents a distinct form due to phase shifts and differences in magnitude. For example, considering an accelerometer over the rear bogie and another one over the front bogie on the same side, they will be in phase for bounce mode responses and out of phase for pitch mode responses [4]. Regarding magnitude, acceleration at coach extremities is expected to be more significant than at the body centre [40,48].…”

“…• n is the background vibration due to the traction motor vibration, the auxiliary power system and the heating, ventilation, and air conditioning (HVAC) system [4,74]. For the considered trailer coaches, there is not component due to the traction motor.…”

“…For railway infrastructure management, the periodic inspection of track quality is fundamental to ensure proper dynamic behaviour of the train-track system and, thus, a safe operation and a comfortable ride. For this inspection activity, the use of dedicated self-propelled or hauled vehicles, such as track recording (or track geometry) cars and trains, is a well-established technique [1][2][3][4] and a more productive alternative to the traditional survey with topographic instruments, the visual inspection, and the manual track geometry trolleys.…”

“…In order to fit the inspection activity to average running speeds even in high-speed lines, the most modern track recording vehicles technologies mainly employ optical system (noncontact) and inertial sensors (response-based) to gather geometry data [4,5], i.e., the surveying of designed geometry and its defects/irregularities. Examples of these concepts are the modern track recording trains that are similarly designed or converted from commercial passenger trains or coaches [3,6,7].…”