# Analysis, Evaluation and Simulation of Railway
## 1 Introduction
### Train Simulators  
The simulation of railway systems has been a field of interest for researchers since the early '80s. In 2008 the Technical University of Cartagena (UPCT), Department of Electrical Engineering, envisaged the usefulness of developing a train energy simulation software. The main reason was the fast development of high-speed services in Spain, and the high energy demand for these trains that affects the whole Power Systems (e.g., balancing of phases in 25 kV substations for high-speed tracks). Moreover, other important issues being considered were sustainability and social equity: The  
Figure 3: Graphic timetable for the railway route Alčázr de San Juan (AJ) to Chinchilla (CH) from 6 p.m. to 12 p.m. on weekdays. Passenger trains in green, freight trains in blue, commuter trains in red and regional trains in maroon. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Station** & **Substation** & \begin{tabular}{c} **Km from Madrid** \\ **and Substation** \\ **Distance 1 (km)** \\ \end{tabular} & **Acronym** & \
\begin{tabular}{c} **Max. Speed** \\ **(km/h)** \\ \end{tabular} &
\begin{tabular}{c} **Trains Flow 2** \\ **(Weekly, 2010)** \\ \end{tabular} \\ \hline Alcazar SJ & Alcazar SJ & 148.5; 0 & AJ & 160 & 110 + 105 + 164 \\ Rio Zancara & Rio Zancara & 171.9; 23.4 & RZ & 200 & 69 + 57 + 168 \\ Socuellamos & Socuellamos & 188.1; 16.2 & SO & 200 & 69 + 57 + 168 \\ Villarrobleo & Villarrobleo & 201.8; 13.7 & VB & 160 & 69 + 57 + 169 \\ Minaya & Minaya & 223.6; 21.8 & MY & 160 & 69 + 57 + 169 \\ La Roda & La Roda & 240.4; 16.8 & LR & 160 & 69 + 57 + 169 \\ La Gineta & La Gineta & 257.7; 17.3 & LG & 160 & 69 + 57 + 169 \\ Albacete & Albacete & 276.2; 18.5 & AB & 200 & 69 + 57 + 180 \\ Chinchilla & Chinchilla & 292.2; 16.0 & CH & 200 & 69 + 32 + 180 \\ Murcia & NA & 460; NA & MU & \textless{}160 & 61 + 0 + 29 \\ Cartagena & NA & 525; NA & CT & \textless{}160 & 66 + 80 + 23 \\ \hline \hline \end{tabular}  
* Distance from previous substation, CH is the last substation; 2 Intercity + regional/commuter + freight.  
\end{table} 
Table 3: Characteristics of the 66 kV-AC/3 kV-DC substations. decrease in interest on conventional low traffic non-electrified lines (the case of the route under study) which deserves small/medium cities and rural areas (i.e., social and economic barriers arise for these areas whereas the development and migration to big cities is stimulated). This possibility resulted in the development of simulator software in Matlab [32; 33]. The main purpose of the program was to calculate the energy consumption, energy recovery, and running times of trains. Obviously, there are various simulation programs developed both by Universities, Engineering Service Companies and the Railway manufacturing industry. For instance, there are commercially available software packages, such as Trainops ([34] developed by LTK) and Sitras Sidytrac ([35], developed by Siemens). Available programs developed by Universities include: Train Operation Model [36] developed by Carnegie Melon University; OpenTrack by ETH university [37; 38], Vehicle Simulation Program (VSP) by Vrije University of Brussels [39] or STEC by KTH (Sweden [20]). The main advantages of this software, and the reason why it is used in this work, is the flexibility that allows for a build-on customization and the integration with other packages of the research team, for example Physically Based Load Models (PBLM) for the evaluation of Energy Storage and Demand Response beyond tractive loads, or the aggregation and management of these resources (from a stochastic point of view). To simulate energy consumption and performance for different train types and categories (freight or passenger), one must first state their properties in the program (tractive effort, braking curves, weight of coaches or wagons, pneumatic braking characteristics, maximum speed, etc., needs to be defined together with number of seats, occupancy, load factor and so forth).