In respect to the interaction between pantographs and catenaries of the straddle-type monorail system of Chongqing urban rail transit Line 2, there occurred the uneven wear of collector slide.

It analyses the rail transit DC traction power supply system voltage type frame protect device and rail voltage limited device matching problems that solve their adjusting value and time.

Aimed at the transit inconvenience of small-size rammer, this paper has designed a type of carrier mechanism.