The capability of railway emergency rescue can be enhanced by maintaining the railway emergency rescue network and upgrading its technology. Nowadays, influenced by the factors, such as resource type, personnel distribution, line level, etc., space-time differences may be unavoidable. In the meantime, the general description method of the transportation network may lack the consideration of the rescue transportation particularity, so the strategies of resource allocation, maintenance, and upgrading could be illogical. Hence, in this paper, the gravity model is utilized to improve the classical travel time budget model and to construct the space-time accessibility model, firstly. Then, further exploring the space-time accessibility of nodes and edges of railway emergency rescue network and considering the randomness of travel time, a space-time accessibility measurement method for an emergency network is proposed. Moreover, a global optimization model with accessibility characteristics is then constructed for the maintenance allocation of the emergency rescue transportation network. The results show that the proposed method can solve the maintenance allocation problem of the large-scale rescue network effectively, reduce the risk of maintenance allocation strategy failure caused by unreasonable node index parameters, and provide an effective basis and theoretical support for the rational formulation of railway rescue transportation network maintenance allocation strategy.