About the person

The challenge

Public transport in a city is of huge importance for the sustainable transport of passengers and the management of the traffic flows of people who use it every day on their way to work or for other journeys. Rail transport using trams is theoretically superior to road transport due to the lower friction between wheel and rail, as more people can be transported using less energy. But in practice, both rail and bus transport are needed, because the transport facilities for trams are particularly exposed to high loads, which is why regular renovation work is necessary. How do you build transport routes that can cope with everything and last as long as possible?

From the lecture

The heaviest means of transport in urban public spaces are buses and trams. Nevertheless, both place different demands on transport routes. The load applied to the rails by the wheels of trams is unsprung, whereas the load applied to the road by buses is sprung due to the tyres of the buses. In many places, however, and especially in particularly busy places, buses and trams share the same traffic areas. This raises the question how such combined transport routes can be built that meet the requirements of both modes of transport. Roads are basically composed of layers of different materials, with an asphalt surface as the top layer. Depending on the thickness of the layer, these are categorised into different load classes, which should meet the relevant load requirements.On combined transport routes, however, the road is interrupted by rails. Different load-bearing capacities on the rails lead to a significantly higher load, which often results in the lowering of the traffic surface at these points. The double load from trams and buses means that the traffic areas often have to be repaired. Increasing the density of the asphalt would increase the durability of traffic surfaces, but in practice this is usually done manually and with small equipment, which leaves more hollow spaces in the asphalt which impair the load-bearing capacity. These hollow spaces can be analysed using the asphalt petrology method. Furthermore, the availability of methods for testing the load-bearing capacity of carriageways is also important. The Falling Weight Deflectometer (FWD) is used for the non-destructive determination of the load-bearing capacity, which makes it possible to measure the depression of the road surface. The interface between rail and road is a major challenge for transport infrastructure construction, especially as there are no uniform standards for cities and communities.

Perspectives

There is huge potential for optimisation in the construction of combined traffic areas for buses and trains. This affects both the asphalt and joint construction as well as the maintenance-friendliness of the systems used. The variety of existing construction methods allows different experiences with different systems. However, more uniform standards remain a desire.