B-unit
01
B单元, B机车
a non-powered locomotive unit that is coupled with a powered locomotive to provide additional traction or increase hauling capacity on trains
例子
The B-unit was coupled behind the lead locomotive to help pull the heavy freight train up the steep incline.
B-unit被连接在牵引机车后面，以帮助拉动重型货运列车上陡坡。
The railroad company used B-units strategically to enhance the efficiency of their long-distance freight services.
铁路公司战略性地使用了B-unit来提高其长途货运服务的效率。
