## 1 Introduction
On the other hand, only a few studies have attempted to control derailed trains to their intended domains. The research related to the method of installing a special device on the vehicle's bogie frame is as follows. [PERSON] et al. [16] developed an \"L-shaped Guide\" that can be attached to a bearing box to control the lateral movement of a derailed train and installed it on a shinkansen train, etc. [PERSON] et al. [17; 18] developed a post-derailment stopper which is attached to the bogie frame. Moreover, a vehicle dynamics model was developed to analyze the post-derailment behavior of a bogie frame with a stopper attached. [PERSON] et al. [19] developed a device to control derailed vehicles and verified their performance through experiments. The research related to the method of installing a protection facility around the track has mainly been conducted by [PERSON] et al. [1; 2; 20]. [PERSON] et al. [1] developed a finite element model for derailment and collision analysis using the LS-Dyna program and evaluated the containment capacity and crashworthiness of the DCP installed in South Korea. [PERSON] et al. [2] analyzed the effect of containment after derailment for various DCP types and suggested the range of possible collision loads for each type. Through such a series of papers, [PERSON] et al. proposed that installation of derailment containment provisions as robust blocks within track gauge (DCP Type I) has many advantages in terms of economics, durability, and efficiency due to the reduction in lateral collision load in comparison with a DCP on the outer side of the track (DCP Type II, III). The finite element model developed by [PERSON] et al. [1; 2] is an effective method for simulating the derailment/collision phenomenon of a vehicle, but it has the disadvantage of consuming huge computational cost and time. Therefore, [PERSON] et al. [20] and [PERSON] et al. [21] developed a simplified FE model that can evaluate the dynamic behavior after derailment without significant errors compared to complex vehicle models. Moreover, this simplified vehicle model was verified through the full-scale tests on bogies and flat wagons running on a concrete track where DCP type I was installed. However, it is difficult for these FE models to perfectly reproduce the behavior of the full vehicle (colliding with DCP and motion after collision). Therefore, a collision test with various DCPs should be performed on an experimental vehicle that can show full vehicle effects such as the center of gravity, connection between cars, etc. The FE model should be improved through these additional experimental studies. Moreover, in order to develop the design specification of DCPs, functionality analysis such as collision (impact) load, collision energy, installation location, size, and containment effect should be performed experimentally and analytically. Therefore, the present research team conducted a functionality analysis of DCPs through the full-scale derailment test firstly. Then, based on the improved simplified FE model, a design specification for DCP was developed. This result will be introduced in the future. In this paper, the functionality of DCP type I was analyzed experimentally. The derailment test cars were a flat wagon and container wagon, and a robust concrete block structure in the form of DCP type I was installed on a concrete track. A method for estimating the collision (impact) load acting on the DCP was proposed. In addition, the containment effect of DCP type I according to the change of the vehicle's center of gravity was identified through a comparative analysis of the dynamic motion for a flat wagon and container wagon such as roll, pitch, and yaw. In the companion paper, the results of the comparative analysis of the functionality of DCP type I and III are presented for a connected vehicle that reflects the connection effect between the cars.