## 5 Discussion
### Relevance for Science and Practice
#### 5.2.2 Generalization of the Core Results
\begin{table}
\begin{tabular}{l l} \hline \hline
**No.** & **Working Hypotheses** \\ \hline \multicolumn{2}{l}{_Conclusions on the developed GIS:_} \\ \multicolumn{2}{l}{VALIDITY} \\ \multicolumn{2}{l}{WH 1} & \multicolumn{1}{c}{\(\bullet\)} & \multicolumn{1}{c}{\({}^{\prime}\)The developed GIS is practical and suitable for the implementation of DTs, which are to digitally represent assets of German rail transport that are in operation.”} \\ \hline \multicolumn{2}{l}{APPLICATION} \\ \multicolumn{2}{l}{\(\bullet\)} & \multicolumn{1}{c}{\({}^{\prime}\)No separable boundaries can be drawn in the practical application of the developed GIS. Thus, it may be useful to keep a list including all processes, which will enable the cross-process storage of relevant information at an early stage.”} \\ \multicolumn{2}{l}{\(\bullet\)} & \multicolumn{1}{c}{\({}^{\prime}\)The GIS can serve to create empirical values in the implementation of DTs. Based on these empirical values, representative GIS versions for individual asset groups can be established (i.e., DTs of ICE trains, DTs of railway infrastructure), which enable a standardized and targeted-oriented implementation of several DTs of the same asset group.”} \\ \multicolumn{2}{l}{_Conclusions on the DT in German rail transport:_} \\ \hline \multirow{2}{*}{WH 3} & USE CASE \\ \multicolumn{2}{l}{\(\bullet\)} & \multicolumn{1}{c}{\({}^{\prime}\)For the implementation of a DT, there must be a specific use case for which the DT represents the operationally optimal solution. Otherwise, the implementation must be refrained from.”} \\ \hline \multicolumn{2}{l}{DATA} \\ \multicolumn{2}{l}{\(\bullet\)} & \multicolumn{1}{c}{\({}^{\prime}\)Data represents a central role in the implementation of a DT in German rail transport. Their requirements must be defined in an application-oriented manner, i.e., based on the concrete operational challenge.”} \\ \multicolumn{2}{l}{\(\bullet\)} & \multicolumn{1}{c}{\({}^{\prime}\)Transmission of real-time rail traffic data is not necessary in normal operations. They are limited to irregular cases such as fault clearance. Thus, some care is needed when using the term real-time with reference to DT.} \\ \multicolumn{2}{l}{\(\bullet\)} & \multicolumn{1}{c}{\({}^{\prime}\)Acquiring condition data of a train asset enables condition-based maintenance and forms the foundation for predictive maintenance.”} \\ \multicolumn{2}{l}{\(\bullet\)} & \multicolumn{1}{c}{\({}^{\prime}\)Acquiring data from a train’s TCMS is only accessible through dialog with the manufacturer, otherwise the train operator will face resource-intensive reprogramming and re-registration. Here, the creation of a win-win situation is necessary. In the future, this data access will be facilitated by a simplified ethernet-based TCMS.”} \\ \hline \multicolumn{2}{l}{WH 5} & DT LIFE CYCLE \\ \multicolumn{2}{l}{\(\bullet\)} & \multicolumn{1}{c}{\({}^{\prime}\)From a current perspective, along the value chain of an asset, multiple DTs will exist.”} \\ \multicolumn{2}{l}{\(\bullet\)} & \multicolumn{1}{c}{\({}^{\prime}\)The introduction of DTs in train tender processes simplifies the reconciliation of requirements immensely and has the potential to serve as the basis for the DTI of the developed train within its operational phase. Furthermore, the inclusion of DT standards within tender procedures creates the potential to establish generally applicable standards in rail transport. With a view to other industries, there is a need for action in this regard.”} \\ \multicolumn{2}{l}{\(\bullet\)} & \multicolumn{1}{c}{\({}^{\prime}\)The use of DTPs, which were used for the design and development of a train, can be profitable for the implementation of a DTI.”} \\ \hline \multicolumn{2}{l}{WH 6} & INTEROPERABILITY and STANDARDS \\ \multicolumn{2}{l}{\(\bullet\)} & \multicolumn{1}{c}{\({}^{\prime}\)The interoperable operation of DTs (DTAs) requires not only technical standards but also a situationally adapted organizational structure, since the regulatory framework of German rail transport makes interoperable exchange difficult.”} \\ \multicolumn{2}{l}{\(\bullet\)} & \multicolumn{1}{c}{\({}^{\prime}\)Within the implementation of DTs, a bundling of activities is needed to ensure a common thrust. This is indispensable for the ability to operate interoperable.”} \\ \multicolumn{2}{l}{\(\bullet\)} & \multicolumn{1}{c}{\({}^{\prime}\)Establishing DT standards can only be done in dialogue with stakeholders as well as industry.”} \\ \hline \multicolumn{2}{l}{WH 7} & PARTNERSHIPS \\ \multicolumn{2}{l}{\(\bullet\)} & \multicolumn{1}{c}{\({}^{\prime}\)In the context of DT research and development, participation of (inter-)national rail transport companies in} \\ \multicolumn{2}{l}{consortia are recommended. Here, the initiation of a rail transport-specific consortium can be useful.”} \\ \multicolumn{2}{l}{\(\bullet\)} & \multicolumn{1}{c}{\({}^{\prime}\)In the context of digitalization, rail transport can use empirical values from other industries, for example with reference to the simulation of capital-intensive assets.”} \\ \hline \multicolumn{2}{l}{\(\bullet\)} & DT VISION \\ \multicolumn{2}{l}{\(\bullet\)} & \multicolumn{1}{c}{\({}^{\prime}\)Achieving the goals of a digital rail system requires modern systems and approaches. In this context the DT, due to its intended interoperability, provides a unique opportunity for data management as well as the connection of promising services, such as the creation of networked and complex analyses and simulations of different (sub-) systems. These serve to increase the reliability and availability of rail transport fundamentally.”} \\ \hline \hline \end{tabular}
\end{table}