From 2000 to 2015, the cost of operation and maintenance (including reinvestment) and traffic control has increased from approximately three billion to over nine billion Swedish kronor annually. By making more frequent measurements of track irregularities and identifying trends earlier, accurate and effective maintenance can be performed. Therefore, in the industry and academy, different measurement solutions are tested to measure the state of railroad tracks in a simple and more frequent manner. One of the solutions is to use measuring systems mounted on trains in regular traffic. By using regular scheduled services, a higher cost effectiveness regarding inspection frequency can be achieved. When the measuring equipment is mounted on freight trains, a measurement with considerably higher axle load can also be performed. In the course of this work, a literature study have been conducted and a number of scientific articles and reports have been studied at depth. There is a number of different systems that have been manufactured to be mounted on rolling stock in regular service. Different solutions are applied to perform the measurements. Acceleration sensors are robust and reliable, which is necessary because they will be mounted in an exposed environment. A difference that has been identified is the installation of accelerometer sensors that are either mounted before or after the primary suspension. Before suspension the sensors are mounted on the axle box and, after suspension the sensors are mounted on the train bogie. The engineering company Damill is working within monitoring solutions and has developed equipment for mounting on trains in regular traffic called Tracklogger. Earlier evaluations of the equipment have been made with focus on comparison with machine inspections. There is a difference between the technology used in track recording vehicles and the technology that Tracklogger uses, such comparison is not entirely appropriate. In discussion with Damill the focus of this work has been to see if recordings of switches can be linked to maintenance actions. Since the equipment is in the development stage it is important that the measurement data collected is critically reviewed with regard to what information it delivers. The measurements have been carried out on switches in the main train track on track number 119 between Luleå and Boden and the mining company LKAB's ore wagon has been a tool carrier.  Five out of eight cases, a maintenance action can be linked to reduced measured values of switches with fixed crossing points. In one case, maintenance action has increased the measured value. In two cases, there is no signifcant difference in the measured value associated with maintenance actions. In previous evaluation, it was determined that it is good repeatability in the measured position, but not as high repeatability in the measured size. A number of switches have been studied to check the repeatability of the measurement. As the train runs in acircle run in Luleå harbor, there will be a limited number of occasions the equipment is running in the same direction in combination with the sensors on the same axle in the bogie, which may effect the measurement results. When analyzing the repeatability of five passages where the direction of travel is not taken into account, it is determined that three out of five passages show a good repeatability. The repeatability of the measurement is suspected of being related to the condition, as significantly greater differences in the measured signal are obtained just before a maintenance action has been taken.