# Towards Intelligent, Programmable, and Open Railway Networks
###### Abstract  
The virtualization and automation of network functions will be key features of future high-speed railway networks, which have to provide dependable, safe, and secure services. The virtualization of railway network functions will enable functions such as train control, train integrity protection, shunting control, and trackside monitoring and maintenance to be virtualized and to be run on general-purpose hardware. Network function virtualization combined with edge computing can deliver dynamic, low-latency, and reliable services. The automation of railway operations can be achieved by embedding intelligence into the network to optimize the railway operation performance and to enhance the passenger experience. This paper presents an innovative railway network architecture that features distributed intelligence, function cloudification and virtualization, openness, and programmability. The focus is on time-tolerant and time-sensitive intelligent services designed to follow the principles of service-oriented architecture. The interaction between identified logical identities is illustrated by use cases. The paper provides some details of the design of the interface between distributed intelligent services and presents the results of an emulation of the interface performance. European Train Control System; artificial intelligence; network function virtualization; service-oriented architecture; concurrent process modeling; key performance indicators +
Footnote †: journal: Applied  
is intended to provide mobile communications between trains, trackside equipment, and a traffic control center. The interfaces installed onboard the train and the trackside system exchange information to control and operate at the maximum allowed train speed. The ERTMS/ETCS can be configured to operate on different levels related to the trackside equipment deployed, the way the information from the trackside is presented to the onboard units, and the distribution of functions between the onboard and trackside equipment. The radio block center (RBC) is an essential ETCS component on Level 2 and Level 3. It is responsible for train guidance and monitoring by receiving the necessary information from the train and trackside equipment and by generating the ETCS travel permits that are sent via the communication network [6; 7]. The Future Railway Mobile Communication System (FRMSC) is the successor of the GSM-R, with the objective of becoming a worldwide standard [8; 9]. The work on the standardization of the FRMCS started with identifying user requirements and went through defining typical use cases and describing the principle FRMCS architecture. The FRMCS will use the public telecommunication networks to connect onboard users, such as automatic train control (ATC)/automatic train protection (ATP), train drivers, shunting staff, passengers, security staff, sensors, and SOS stations, with ground users in data centers for ATC/ATP, in railway offices, at stations and platforms, at depots, and on the trackside. Current fifth-generation (5G) communications can address the requirements of the FRMCS by offering enhanced broadband service, ultrareliable and low-latency services, and massive machine-type services [10; 11; 12]. Fifth-generation (5G) communications and artificial intelligence (AI) are two essential ingredients that drive future innovations in the railway industry [13; 14]. 5G communications make it possible to provide connectivity, and AI can provide the ability of onboard, trackside, and ground devices to not only perceive, reason, and act intuitively, but also to solve technical challenges. AI advancements can help to improve railways' performance and efficiency, while 5G connectivity of railway assets can fuel distributed intelligence at the edge. Edge intelligence can satisfy the rising requirements of critical railway applications [15; 16; 17]. The authors' previous research presented the idea of the disaggregation of the ETCS's radio block center functionality following the principles of openness and intelligence [18].