The Jungfraujoch in the Swiss Alps is a must-see attraction. The Jungfraujoch is a particular favorite of tourists from the Far East. To see Jungfraujoch, you can now go via modern or historic railways. However it is annoying, if on the way to this fantastic place, noises suddenly occur in one of the railcars. But how dangerous these noises are, was a question to be answered using measurement technology. Or better yet, what can be done to eliminate this noise? A diagnostic order that is undertaken with glee. Fig. 2 shows a rack and pinion drive found in historic railcars. Accelerometers were mounted to characteristic measurement points of several drives, and a microphone installed inside the train. For data acquisition a mobile online CMS was temporarily installed in the train, to enable real-time measurement evaluation and diagnosis during the measuring run. Then the run began with an additionally coupled, fully filled water truck to simulate the passenger mass. It was apparent that the train changed gear in narrow curve sections both during the ascent and the descent, which needed to be considered as part of the evaluation.