## 2 Method to Measure Railway Station Infrastructure Quality  
At DB Station&Service AG, and thus for the infrastructure of railway station assets, one of the quality indicators currently used is the assessment of asset quality (\"Bewertung Anlagenqualitat\" (BAQ)). The BAQ is a quality indicator that describes the quality of the infrastructure using a nationwide grade. To yield this grade, single infrastructure assets are first graded and then are aggregated for all assets in the DB Station&Service AG network. The scale of the grade ranges from 1 (best possible quality) to 6 (poorest possible quality). The following section describes the basic idea of the method applied for the determination of the BAQ grade. The details of the determination of the BAQ grade, however, are described in the LuFV III [7]. For BAQ grade determination, individual assets (e.g., a platform) are first assessed by employees of DB Station&Service AG. The abrasion and damage to the individual assets observed are converted into a score. For this purpose, different reference damages and weights of the damages on the components of the assets are used, which are individual for each asset. After weighting the different components of an asset, the asset receives a score. This score can then be converted into a grade. The score ranges from 0-240 points, with zero points representing the best possible rating. In Figure 1, the correlation between the score and the grade of an asset is depicted. In the green area, the infrastructure assets are in very good to good condition. In the yellow area, the quality is still satisfactory to sufficient, while in the red area the quality is poor to unsatisfactory. After the determination of the grade for each individual asset, a grade for the entire station is determined from the grades of the individual assets in a station. For this purpose, asset classes are formed. An asset class consists of all assets of the same type. The grade for each asset class in the station is first calculated as the arithmetic mean of all individual assets of this asset class. Some of these asset classes are further combined into asset groups. The \"station buildings\" and the \"platform equipment\" form such asset groups and are then divided into different asset classes, as shown in Table 1. Other asset classes form their asset group. The process for calculating the grades is specified in LuFV III [7] and is described in the following Equations (1)-(4). \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Asset Group**} & \multicolumn{3}{c}{**Weighting within the**} \\  & **Asset Class** & **Asset Group** & **Weighting within** \\  & & **q [\%]** & **Station p [\%]** \\ \hline \multirow{4}{*}{platform equipment} & passenger information systems & 13 & \\  & dodgers (weather protection) & 15 & \\  & windbreaks & 4 & \\  & passenger elevators & 20 & 10 \\  & escalators & 18 & \\  & ramps on platforms & 15 & \\  & staircases on platforms & 15 & \\ \hline \multirow{4}{*}{station building} & floors and staircases & 10 & \\  & entrance doors & 5 & \\  & flat roofs & 20 & \\  & steep roofs & 20 & 7 \\  & facades & 20 & \\  & windows & 15 & \\  & walls & 10 & \\ \hline \multirow{4}{*}{station building} & platforms & - & 30 \\  & platform roofs & - & 9 \\  & underground passenger stations & - & 9 \\  & platform halls & - & 15 \\  & pedestrian overpasses & - & 1 \\  & pedestrian underpasses & - & 14 \\  & lighting poles & - & 5 \\ \hline \(\Sigma\) & & 100 & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: List of station infrastructure classes and their weightings for BAQ aggregation [7]. Figure 1: Conversion from the score to grade according to [7]. The grades for the asset groups are added up to one group grade according to their weighting (Equation (1) [7]). Here, the factor \(q\) indicates the weighting within an asset group:  
\[BAQ_{group}=\sum_{i=1}^{num\ classes}\varnothing grade_{class\ i}\cdot q_{i} \tag{1}\]  
Not every asset group includes multiple classes.