*Article* **Fault Detection for High-Speed Trains Using CCA and Just-in-Time Learning**

**Hong Zheng 1, Keyuan Zhu 1, Chao Cheng 1,\* and Zhaowang Fu 2**


**\*** Correspondence: chengchao@ccut.edu.cn

**Abstract:** Online monitors of the running gears systems of high-speed trains play critical roles in ensuring operational safety and reliability. Status signals collected from high-speed train running gears are very complex regarding working environments, random noises and many other real-world constraints. This paper proposed fault detection (FD) models using canonical correlation analysis (CCA) and just-in-time learning (JITL) to process scalar signals of high-speed train gears, named as CCA-JITL. After data preprocessing and normalization, CCA transforms covariance matrices of high-dimension historical data into low-dimension subspaces and maximizes correlations between the most important latent dimensions. Then, JITL components formulate local FD models which utilize subsets of testing samples with larger Euclidean distances to training data. A case study introduced a novel system design of an online FD architecture and demonstrated that CCA-JITL FD models significantly outperformed traditional CCA models. The approach is applicable to other dimension reduction FD models such as PCA and PLS.

**Keywords:** canonical correlation analysis; just-in-time learning; fault detection; high-speed trains
