A Review of Railway Track Laboratory Tests with Various Scales for Better Decision‐Making about More Efficient Apparatus Using TOPSIS Analysis

Abstract

Improving the performance of railways depends on increasing their efficiency and the speed of locomotives, which is provided by improving the infrastructure of railways. Therefore, in various studies, researchers seek to modify ballast materials, sleepers and rails, or to study various geometric and environmental conditions in order to reduce the existing weaknesses of railways. Therefore, in order to evaluate the above conditions, various tests should be performed on railways. Some of the tests take place in the field when the train is passing. However, these tests have various limitations and endanger the safety of researchers and are associated with difficulties. Therefore, many tests are performed using various apparatuses on a laboratory scale. In this study, by reviewing different apparatuses used by researchers to simulate loading on the railway, they were compared and by examining different criteria such as loading type, different loading directions, scale of apparatuses, static and dynamic simulated loads and other environmental and geometric conditions, the best apparatuses on a laboratory scale are recommended for simulating vertical, longitudinal and lateral loads and measuring noise and vibration. By the use of TOPSIS analysis on 16 introduced apparatuses from reviewing different studies, it was found that the scaled railway track model had the first rank among different apparatuses and by modifying the weaknesses of this apparatus, it can be turned into the most comprehensive laboratory apparatus to simulate the loading of railway tracks with a scale of 1 : 5. Among the introduced apparatuses, wheel on roller test rig and roller rig had the second and third ranks, respectively, the apparatuses of which usually have a scale of 1 : 5 and deal with the interaction between the rail and the wheel and the impact of the vehicle on the railway track.

The Environmental Impact of Anti-Icing Materials on Asphalt Surfaces (Commonly Used Anti-Icing Agents)

“…These values, obtained based on laboratory experiments reported by the aforementioned references, are presented in Table 3, with the units of each parameter specified in the first column. Subsequently, using the TOPSIS method [11], the weights of different parameters were determined according to Figure 2. According to this figure, metal corrosion and the acidity or alkalinity level of the anti-icing materials have the highest weights.…”

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Towards a comprehensive COVID-19 non-pharmaceutical interventions’ index for the province of Quebec.

“…The Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) was utilized to determine the weights of each category, mathematically [13]. In this method, m categories were evaluated by n sub-categories, and n sub-categories were evaluated by x interventions.…”