It's not that you can't learn anything in a training school, but it depends on the school you attend. My friend told me about a school in Luoyang, an excellent class jointly run by Luoyang Juke Excavator Maintenance Factory and Luoyang University of Technology. "1+2" teaching mode, one month of system theory knowledge, two months of practical maintenance, professional training and professional creation, including one month of high-density electrical, hydraulic and professional training in university campus. You can also check it, www.wajueji.cn.