An on-demand stop usually means waving at the driver at the stop. Here, it works completely differently: the potential passenger has to press a push button, which will cause the driver of the tram to see a red light. There are a lot of local reasons for working with this system: the higher speed of the tram, the lack of visibility (due to curves), the very short stop platform (where only a small part of the tram can stop), the location in the middle of a dark forest, where walkers come especially during the day.