On February 22, 2019, China's first variable marshalling unit completed all more than 60 in-plant tests at China's China Railway Tangshan Company, and passed the unique variable marshalling verification, with factory conditions.

Prior to this, the EMU has applied for nearly 80 patents and won the China Excellent Industrial Design Award and the China Design Intelligent Manufacturing Award.

Since the birth of high-speed EMUs for more than half a century, relatively fixed marshalling methods have been widely used. Railway transportation is divided into low and high seasons of passenger flow, and there is a huge difference between the Spring Festival and daily. Fixed marshalling EMUs cannot be disassembled, cannot increase carriages to cope with peak passenger flow, nor can they reduce carriages to reduce expenditure or avoid waste of capacity. Passenger flow and capacity often form bottlenecks.

In the new models of variable group EMU, double-decker second-class cars, double-decker VIP cars, double-decker meal and passenger and cargo cars are all double-decker structures.

The minimum marshalling unit of the variable marshalling EMU is two sections, I .e. two power head cars are connected.

In the face of changes in passenger flow, if the marshalling is to be expanded, the optimal matching of efficiency will be calculated according to the speed and power, and the matching of motor cars and trailer cars will be changed at will within the range of 2 to 16 knots. EMU trains with different speed grades, marshalling numbers and seating configurations will be quickly customized, which is as flexible as "building blocks.

In areas with large passenger flow, double-deck, long-marshalling and large-capacity EMUs can be used; in economically developed areas, comfortable and large-space short-marshalling trains can be used; in areas with low passenger flow, short-marshalling trains can be used.

Through its own "72 changes", the variable marshalling EMU can flexibly respond to the ups and downs of passenger flow and passenger demand, significantly improve the cost performance and practicability of EMU trains, and conform to people's yearning for a better travel life.

When you are in the train, you can better realize the new design concept of "smart and intelligent", "complete with five internal organs", "completely new" and "economic comfort.

The intelligent network control system based on the EMU can automatically identify the grouping configuration when changing the collocation of the carriage, and passengers can enjoy the functions of intelligent storage of large luggage and intelligent ordering of meals. While realizing the full WiFi network coverage, the sleeper passengers can adjust the lighting and video system of the berth according to their needs... Significantly improve the comfort of passengers.

Large-capacity vertical sleeper cars, double-decker cars and business cars have increased their carrying capacity by 50%, 33% and 70% respectively compared with conventional high-speed trains, which can increase the floating space of fares in the off-season and greatly increase the capacity to cope with the peak passenger flow in the peak season.

At the same time, the variable marshalling EMU has also added an independent warehouse to the lower layer of the food and cargo and passenger and cargo combined vehicles, which can realize the functions of small insulation, refrigerated containers, express mail and luggage fast transportation, fill the gap of EMU freight transportation, and will have a profound impact on the logistics industry such as fresh product transportation and medical and health first aid.

Industrialized platform variable marshalling EMU provides more choices for high-speed rail to further optimize passenger travel conditions.

The R & D team implements the concept of deep integration of industrial design and manufacturing, breaking through key technologies such as traction power system integration, network control, and vehicle end connection, using modular, integrated, and unit design to break the fixed marshalling mode of high-speed trains, and redesign and define the equipment, functions and structure of EMUs, new models such as double-decker cars, large-capacity longitudinal sleeper cars, seat-horizontal VIP cars, business seat cars, seat-to-sleeper conversion sleeper cars, food and cargo and passenger-cargo combined cars have been developed.

In the field of double-decker EMUs, CRRC Tangshan has strong technical strength and rich product experience: in 1998, they developed China's first double-decker internal combustion EMUs and opened the "Lushan" intercity tourism train. In 2017, they won the bid for the Philadelphia double-deck EMU project in the United States, and China's rail transit equipment, especially stainless steel double-deck cars, was exported to North American trunk railways for the first time.