Abstract: The present disclosure relates to a device and a system for testing flatness. The device for testing flatness includes a base, a testing platform, and a ranging sensor. The testing platform is assembled on the base. The testing platform includes a supporting structure. The supporting structure is disposed on the side of the testing platform away from the base and is used to support a to-be-tested board. The structure matches the structure of the to-be-tested board. The ranging sensor is disposed on the side of the testing platform away from the base. After the to-be-tested board is placed on the testing platform, the ranging sensor is used to test distances between a number N of to-be-tested positions on the to-be-tested board and the ranging sensor, to obtain N pieces of distance information, and the N pieces of distance information are used to determine the flatness of the to-be-tested board, where N is an integer greater than 2.

Abstract: Disclosed is a carriage body for a multiple unit train, comprising: a chassis (10) and a power system module mounted in a suspended manner below the chassis (10), an access opening (11) for facilitating to overhaul the power system module is provided on the chassis (10), a passenger compartment floorboard (12) covers top surface of the chassis (10) and surround the access opening (11), further comprising an access door (2) for blocking the access opening (11), which comprises a top panel (21), a reinforcement panel (22), and a sound-insulation panel (23) for sound-proofing, which are provided successively from top to bottom, and are fixedly connected as one piece; the periphery of the top panel (21) engages with the passenger compartment floorboard (12); the top panel (21) is detachably yet fixedly connected onto the floorboard (12) of the passenger compartment and/or the chassis (10).

Abstract: Disclosed is a carriage body for a multiple unit train, comprising: a chassis (10) and a power system module mounted in a suspended manner below the chassis (10), an access opening (11) for facilitating to overhaul the power system module is provided on the chassis (10), a passenger compartment floorboard (12) covers top surface of the chassis (10) and surround the access opening (11), further comprising an access door (2) for blocking the access opening (11), which comprises a top panel (21), a reinforcement panel (22), and a sound-insulation panel (23) for sound-proofing, which are provided successively from top to bottom, and are fixedly connected as one piece; the periphery of the top panel (21) engages with the passenger compartment floorboard (12); the top panel (21) is detachably yet fixedly connected onto the floorboard (12) of the passenger compartment and/or the chassis (10).