Traffic Load and Its Impact on Track Maintenance

Abstract

Transport volume is often addressed as gross-tonnage when it comes to track degradation, maintenance needs and maintenance costs. Tonnage and thus weight are insufficient to address track loading: The vehicle properties, mainly axle load, unsprung masses and bogie stiffness, as well as train speed have a major impact on track maintenance demand. This chapter gives an overview on vehicle-specific track deterioration models and describes the maintenance needs of different track as well as the influence on track maintenance cost of different vehicles and trains. The approach proposed is both simple enough to be used and sufficiently detailed to address the main technical aspects. The differences of track maintenance necessary for mixed traffic lines, high-speed lines and heavy haul freight lines can be derived from the vehicles used and the existing train speeds. In passenger transport, the difference between push-pull loco hauled trains (with wagons) and multiple units are a major aspect.

Track Deterioration Model—State of the Art and Research Potentials

“…The Track Deterioration Model (TDM) this paper focuses on is published and explained in depth by Marschnig et al [1]. The discussed model is a further development of and is based on the Swiss TDM that was implemented in the network of the Swiss Federal Railways (SBB) as a track access charging tool in 2017 [2].…”

“…The basic idea of this TDM is to combine maintenance costs, frequencies, and investment costs with empiric-analytical descriptions of track component deterioration on ballasted tracks, which include vehicle and infrastructure parameters in their formulas. In Equation (1), the general methodology of the TUG TDM is depicted. The aim of this formula is to calculate/estimate the total costs per vehicle kilometre that are induced by a certain vehicle on a certain track segment.…”

“…The product of each D n × c n lead to costs per kilometre. Further details on the general model approach and the cost calibration factors c n can be found in [1,3], as this review focuses on the description of damage mechanisms on ballasted tracks and, therefore, on the damage terms D n . In Equation (2), the complete wear formula is depicted, whereas in Equation ( 3), an equation of units is added to clarify the methodology of the TUG TDM.…”

“…The traction power value (TPV) is calculated by determining the power of a vehicle relative to the contact area between the rail and wheel, as Equation ( 21) shows. It is important to note that TPV is only applicable to powered wheelsets [1].…”

“…Existing Track Deterioration Models aim to link vehicles' input on tracks with the deterioration or damage of track components. All these models have two common basic principles: (1) The damage terms describe an average situation, as they are based on empirical and, thus, statistical analyses, so varying boundary conditions, especially track conditions, are not addressed. (2) The aim of these models is foremost to allocate track costs accordingly to vehicle properties and train speeds.…”