Developing a Technical-Economical Method for Selection of Railway System (Ballasted/Ballast-less)

The railway system selection(ballasted/ballastless) issue is usually a function of technical criteria and life cycle costs. In this paper, the IRSST decision-making model or railway system selection is developed based on both technical and economic criteria. In this regard, by developing a Python based computer model according to the requirements of IRS 70727, in the first step, the track system in mandatory sections of the route of Qom-Isfahan high speed railway in (Km 5 + 000 ~ Km 29 + 110) area zone was determined based on restrictive technical criteria, and then for other sections of the route, the track system was selected based on life cycle cost (LCC). Since the track system LCC is commonly a function of inflation rate (i) and discount rate (r), the proposed values of these parameters in IRS 70727 were adopted in absence of Iran railway routes accurate data. For sensitivity analyses purpose the range of 0≤i≤3 and 0≤r≤8 was adopted and their effect on LCC and consequently the track system selection was investigated. Finally the outcomes of the sensitivity analyses were presented in the form of “variation of the track system along the track route”, “total length of ballasted and ballastless systems” and “Kernel density estimation curves (KDE)” for various values of i and r. Definitely it was observed that I the case of r≥3 and for each value of i, the of track system is ballasted while for 0≤r≤3 and all i values, the track system was ballastless.