## 2 Materials and Methods
### Simulation Test Setup  
Three countermeasure design concepts were developed, each targeting a specific area of injury causation. highlighted by [15] primary-contact, secondary-contact, and run-over injuries. These designs are intended to work synergistically to provide a holistic approach to injury mitigation. While their combined use holds the potential for significant safety benefits, their effectiveness remains subject to further evaluation, and practical challenges such as manufacturing feasibility and integration into existing subway systems must also be considered. In this study, the MADYMO software package was used to simulate the effect of each countermeasure design on pedestrian head injury and run-over risk. The simulations used the 50 th percentile male ellipsoid model and R160 train geometry developed in [15], as well as a subset of the initial conditions established in that work. Specifically, only the standing and jumping postures were selected, which are based on publicly available video footage (Figure 4). The Front Panel (FP) countermeasure design features hard-shelled energy-absorbing panels mounted directly on the train front down to but not beyond the anticlumber (see Figure 5). Beyond mitigating head injuries, this design also addresses run-over risks through the strategic geometry of the panels. The panel shape is specifically designed to work in tandem with the drainage trough, leveraging its safety potential to redirect pedestrian kinematics away from hazardous areas such as the third rail. The geometry consists of two circles with radii of 0.15 m and 0.25 m, connected by an arc with a radius of 0.75 m, creating a contour with a minimum depth of 0.3 m and a maximum depth of 0.5 m. By positioning the larger curve at the outer edge of the train front, this configuration is designed to guide pedestrians during the free-fall phase of impact, influencing their trajectory toward the drainage trough and potentially reducing the likelihood of critical run-over injuries. To define contact interactions, three ellipsoids were modelled on each side of the train front to approximate the panel geometry with the experimentally derived contact characteristics of an aluminium-covered EAC. This approach allowed for an evaluation of the panel's potential effectiveness in altering pedestrian kinematics and mitigating injuries across multiple scenarios. Figure 4: Representative stills from YouTube videos illustrating 2D keypoints, 3D keypoints, and the subsequent MADYMO pedestrian modelling configuration via KinePose (Adapted from [15]). The second Full Front Guard (FFG) design is aimed at increasing the effective area of the front-panel concept. While the front-panel EAC concept has an effective coverage range extending from the train front to the anticlimber, to ensure standing pedestrians receive the full benefit, this range must be extended further downwards (see Figure 6). While maintaining the same contact characteristics and geometry as the front panel concept, the vertical dimension of the countermeasure was extended such that the panels maintain a clearance of 0.2 m from the rail top (see Figure 5). An additional panel was placed in the centre, covering the coupler while leaving sufficient spacing for the operation of the door. This panel was angled to 45 degrees to further influence pedestrian kinematics toward the drainage trough and away from the third rail. Although more challenging in implementation compared to front panels, the full-frontal-guard concept is expected to have an effect on at least 70% of incidents involving a frontal subway-to-pedestrian collision [7]. Figure 5: MADYMO model of front-panel countermeasure. Figure 6: MADYMO model of full-front-guard countermeasure design. The FP and FFG countermeasure design concepts address primary-contact head injury risk and run-over risk, but little benefit is expected from these designs in terms of secondary-contact head injury reduction. To address secondary contact, a rail covering [Track and Front Guard (TG)] was designed (see Figure 7 ).