## 3 Proposed Approach
### Data Cleaning and Data Transformation  
The purpose of this study is to collect failure record history data on intermittent alarms and to use text descriptions to identify potential factors. Additionally, in order to make sense of the data using a model, it is best to include factors that are not correlated. To identify potential factors from the text description (Table 2), we must also check for under-fitting or over-fitting issues, look for additional features if it is biased, add a regularization term if it is over-fitting. This study identifies three major factors that contribute to trainset instability, which are trainset original problems, rail condition, and operating conditions. It then adds three atmospheric variables [3] to these factors, forming seven major potential factors, which are discussed below:  
1. Factors for trainset original problems are \"Trainset accumulated mileages\" and \"Occurring time\". 2. Factor for rail condition is \"Alarming location\". 3. Factor for operating condition is \"Train speed\". 4. Factors for atmospheric condition are \"Temperature\", \"Humidity\" and \"Rainfall\". \begin{table}
\begin{tabular}{l l} \hline \hline
**TR** & **TEXX** \\ \hline Date & 2012/XX/XX \\ \hline Train No. & XXX \\ \hline \multirow{4}{*}{Description} & TD responded to Car1 failure 502 Bogie Abnormal Motion, occurred at TXXXX, speed XXX km/h, reverted 1 s after failure. TD at the same time cannot detect any bogie instability coming from Cab12. OBC history displays 525 “1-Bogie Instab Det by 1 st Lat Acc Sensor. After that, TM headed to Car to check and respond current status. Please download Cab12 OBC data and Event data Recorder. \\ \hline \multirow{4}{*}{Action taken} & 1. & Download and analyze OBC \& BIDS \& Event data OBC data: \\  & \(\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blackblacklozenge\blackblackblack\) \\  & 14:19:10.180 (Rec) Car1\_0502: Bogie Abnormal Motion (TKXXXX km) \\  & (SpeedXXXkm/h) Car2\_0525: 1-Bogie Instab Det by 1 st Lat Acc sensor \\ \cline{2-2}  & BIDS data: \\  & \(\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blackblacklozenge\blacklozenge\blackblacklozenge\blackblacklozenge\blackblackblackblack\) \\  & \(\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blackblacklozenge\blackblackblack\) \\  & \(\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blacklozenge\blackblack\) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Sample of a Trainset Failure Record. The seven factors mentioned above and their ranking levels are described in more detail as follows:  
1. Alarming location: If a railway line fails to meet the standard for rail lines (rail lines fail to meet the standard for train wheel roundness), although both of them are within the standard value, intermittent alarms can occur easily due to rail/wheel interface problems, leading to the activation of BIDS. Hence, this factor is used to determine if BIDS alarms usually occur at a specific location.