This cast-iron object has a metal base that holds, at the top front, a sheet of plastic with holes in it, marked with the categories of the 1890 U.S. Census of population. In back of this is a holder ...

Abstract: With the increasing speed of urban rail trains, the vibration between the pantograph collector strip and the contact wire intensifies, and the pantograph-catenary arc occurs frequently, ...

There's no reason to get down on your hands and knees to clean your floors. If you want to get the job done with minimal effort, invest in a floor scrubber to do the dirty work for you. Floor ...

Abstract: Sliding friction pair composed of contact wire and pantograph slide is the key component of train current collection system. Contact temperature is one of the important factors affecting the ...