Figure 13
The figure contains two side‑by‑side panels titled “Left wheel‑rail” on the left and “Right wheel‑rail” on the right, each plotting sound level against working condition. The horizontal axis in both panels is labeled “Working condition” and shows three categories: “50 kilometers per hour R 300 meters”, “100 kilometers per hour R 500 meters”, and “160 kilometers per hour R 1300 meters”. The vertical axis in both panels is labeled “Equivalent continuous A‑weighted sound pressure level, decibels (A)” and ranges from 70 to 130 with an interval of 5. In each panel, three tall shaded bars represent sound levels at the different conditions, with a line and square markers connecting the top of each bar. For the left wheel‑rail, the bar tops and markers indicate levels at 121 for 50 kilometers per hour, around 124.5 for 100 kilometers per hour, and just over 105 for 160 kilometers per hour, so the line first rises then drops sharply. For the right wheel‑rail, the pattern is similar: about 120 for 50 kilometers per hour, around 122.5 for 100 kilometers per hour, and just over 107.5 for 160 kilometers per hour. Note: All the numerical data values are approximated.Comparison of results under different working conditions. Source: Authors’ own work