Mechanical engineers think that he has no clue how to control a high speed train down a tube. It is hard enough to make railway tracks straight and have a suitable suspension. In this case he relies on taking the small amount of air in the tube and pumping up to high pressure. This is extremely inefficient and unlikely enough to maintain stable air bearings. He has also vastly underestimated the cost.
傻X媒体（中美皆然）和这儿的部分网友无限抬高Musk，只能暴露自己缺乏科学素养和基本的工程师思维。