With the rapid expansion of China’s high-speed railway (HSR) network across vast territories characterized by drastically varying climatic conditions, ensuring the operational reliability of railway signaling systems under extreme ice and snow conditions has emerged as a critical engineering challenge. During winter operations, the ice and snow chunks that accumulate on electric multiple unit bogies and underframes frequently detach during high-speed travel—particularly when trains cross the 0 ℃ isotherm—causing high-energy impact damage to the wayside equipment. As the core ground device of the Chinese Train Control System, balises are vital for transmitting line parameters, positioning data, and temporary speed limit information to onboard equipment. Over 300000 balise units are in service across China’s HSR network, and their structural integrity directly determines railway operational safety and efficiency. Previous research on balise impact resistance has mostly neglected the influence of the low-temperature mechanical properties of housing materials, leading to significant deviations between the simulation results and field failure cases. Furthermore, systematic analyses of the damage phenomenon under ice–snow impact and targeted improvement measures are lacking. This study aimed to address these critical research gaps.

This study analyzed SMC-4/3394 sheet molding compound, which is the mainstream material for commercial balise housings. First, quasi-static tensile tests and Charpy impact tests were conducted at four temperatures (20 ℃, 0 ℃, -10 ℃, and -20 ℃), representing the actual winter operating temperatures of China’s HSR, to obtain key mechanical data, including full stress–strain curves, elastic modulus, yield strength, and impact strength. Based on these data, a refined full-scale explicit dynamic finite element (FE) model of ice–snow chunks impacting a balise (including the housing, mounting fixture, and ice block) was established using Abaqus software. The damage evolution behavior of the balise under different impact conditions was systematically analyzed over impact speeds of 160–350 km/h (the operating speed range of China’s HSR) and at typical impact positions consistent with field failure data. Finally, parametric simulation studies were performed to identify the key optimization factors for mitigating balise damage.

The material test results show that the elastic modulus of SMC-4/3394 is slightly affected by ambient temperature, whereas its impact strength exhibits a significant increasing trend with decreasing temperature, providing accurate and reliable input parameters for subsequent FE simulations. The FE simulation results indicate that the balise suffers an increasing degree of damage with increasing impact speed and that the critical speed for structural damage initiation is approximately 220 km/h. This conclusion verifies the rationality of existing winter speed limit regulations for the HSR network and clarifies the safety margin of train operations in icy and snowy weather. Furthermore, parametric simulation studies identified two key optimization factors: (1) appropriately reducing the installation height of the balise can significantly reduce the severity of structural damage under the same impact energy and lower the probability of it being hit by falling ice–snow chunks; (2) optimizing the side profile of the balise housing with a bevel structure can effectively reduce the peak stress of the housing, achieving a notable reduction in the damage degree compared with the original right-angle structure under identical working conditions.

This study reveals the damage mechanism of balises under ice–snow chunk impact by comprehensively considering low-temperature material properties, thereby filling a research gap in this field. The research results provide solid theoretical support for formulating science-informed winter operation speed limits for HSR in ice and snow conditions. Moreover, they offer valuable technical guidance for the daily maintenance, fault prevention, and structural optimization of balises.