# Towards the Internet of Smart Trains:
## 6 IoT-Enabled Services: From More Efficient Operations to New Business Models
### Train Control Systems
#### 6.4.2 Safety Assurance and Signaling Systems  
The improvement of the safety is one of the major goals when applying IIoT in railway environments. For instance, an accurate on-board positioning system is essential in order to determine the position of other trains and then avoid collisions, perform safer operations in close proximity and optimize the use of the tracks. Another safety application is related to the measurement and control of the speed [123]. There are currently systems that show the train speed to the drivers and later report it to central control systems. Some of such system are able to interact with wayside signaling systems with the objective of regulating the train velocity and they are even able to stop the train completely if certain conditions are met. There are four major systems where automation and IIoT can bring significant advantages: signaling, level crossing control, interlocking, and dispatching. Signaling systems can adjust remotely the speed and braking of the train. Signaling systems are usually equipped with RFID devices that are embedded into the tracks, but wireless ground-to-train signaling is becoming habitual. Most of the new European lines are equipped with ETCS level 2, as it was explained previously in Section 3, which requires train-to-ground communications. Level crossing control has also a huge impact on safety. According to ERA, in 2010 more than 300 people died in incidents that took place at level crossings, representing 30% of all the deaths related to European railways. IIoT can help to decrease those statistics by deploying cameras and sensors for increased safety. One example in the literature relying on video is presented in [124]. Other alternatives use Ultra-Wide Band (UWB) technologies [125]. Interlocking works together with the signaling system to avoid collisions at crossings and junctions. It essentially makes use of traffic lights and signals that prevent trains from moving forward if a scenario is not safe. IIoT enables the automation of the interlocking system and enhances it by integrating the data received from the signaling system. Furthermore, comprehensive dispatching information including text, data, voice, image, and video, can be provided by drivers and yards to the dispatcher. Supporting functionalities such as voice trunking, dynamic grouping, temporary group call, short messaging, and multimedia messaging, is also needed. For instance, in case of automatic driving, dispatching video stream of doorways is required to ensure that doors are clear prior to the train departure. The data collected from on-board and wayside embedded devices provide a large amount of information that can be exploited through data mining techniques, which allow for the identification of structural patterns that cannot be discovered easily. Several researchers studied the application of such techniques in railway scenarios. For example, [PERSON] et al. [126] exploited the information from the describer records of a train to evaluate potential conflicts associated with the scheduling or the capacity of the railway system. Furthermore, such information is also used in [127] to develop a model for predicting the timing of certain events. The same authors from the previous reference also assessed the viability of using data mining techniques to exploit rail data like business processes [128]. Similarly, in [129] different real-time techniques are studied, but for controlling train traffic. Recently, the authors of [130] proposed the use of fast scheduling and routing metaheuristics for managing train traffic in busy situations, taking special care of the control efficiency in conflictive traffic situations (e.g., multiple train delays). Furthermore, there is a recognized need for providing train locations in real time, which should be compliant with the railway safety requirements [131] (e.g., with the EN 50126 standard). Thus, some researchers evaluated the use of GNSS receivers for train positioning [132].