Before the 1990s, the maximum speed at which services operated in China had long remained at 120 km/h (75 mph) or below, and faced increasingly steep competition from airplanes and highways.

In December 1994, the upgraded Guangshen railway was put into service, which demonstrated the basics for future development of high-speed rail.

[2] To increase the competitiveness of the railways, the ministry set a target for a 200 km/h (124 mph) high speed EMU.

In the Ninth Five-Year Plan, there were two such targets relating to the development of trainsets: The "200 km/h (124 mph) power separated EMU" was designed with the participation of Nanjing Puzhen Rolling Stock, Tongji University, China Academy of Railway Sciences, CRRC Zhuzhou Institute, Datong Locomotive, Yongji Electric, Central South University, and some other minor companies, with Puzhen leading the design.

[5] The design of the set was completed at Puzhen in 1999, and submitted the plan for approval; construction began in August 1999.

In the second such test from 5 to 12 September 2002, the "Xianfeng" collected various data on the traction, braking, behaviour at track switches, the effect on the pantograph at high speeds and the train warning system, while also testing the rails, switches, viaducts and signals of the new high speed line.

[10][11] After travelling 100,000 km (62,137 mi), the Ministry of Railway decided to expand the "Xianfeng" EMU from six to nine cars, and was listed as a task in the Tenth Five-Year Plan, which Puzhen took up, with their design being approved in March 2003.

On 19 December 2006, the ministry held a meeting to summarise the experiences from operating the "Xianfeng" EMU, where it was decided to return it to service as soon as possible, after it undergoes a repair.

[16] On 8 September 2007, the "Xianfeng" suffered its first fault since its start of operation with the Chengdu Bureau, leading to the service being late by two hours.

[17] Between February and March 2008, when the "Xianfeng" underwent repairs, the services were instead carried out by DJJ1 "Blue Arrow" electric multiple units.

[18] To improve the transportation efficiency of the Chenyu intercity trains, the timetable was adjusted on 21 December 2008, which allocated three of the five daily runs to two coupled DJJ1 sets, while the other two were standard double-deck locomotive hauled services.

[24] The car body uses a thin-wall, cylindrical monocoque fully welded design, with a streamlined head made of composite materials.

The traction transformer comprises the four-quadrant rectifier, intermediate DC circuit and the PMW inverter, with an output is 3300V/1200A with water cooling.

Another set of transformers under each trailer and non-driving motor lowers the voltage from 600V to 110V DC to power the control data link on the train.

The train communication network has a connection point for each carriage, and data is transmitted through a frequency-shift keying, dual shielded cable.

The risk of this was made worse by the lower profile of the car, which meant the surface area of the cooling system was increased.

It posed a safety risk, as it was impossible to check whether oil was leaking into the transformer while the train was in motion.

Nonetheless, the FSK required improvements, as it became a bottleneck in train control due to the low bandwidth, and the data loggers were unable to copy out particular errors and had insufficient memory to store all errors, meaning it was hard to perform diagnosis, management and maintenance.