Chinese Rail DF4

Chinese Rail DF4 is a kind of diesel locomotive used in China. It was built by Dalian Locomotive &amp; Rolling Stock Works. It has been in production since 1969 and is still produced as of 1984. 
Models.
DF4.
The first DF4 was built in 1969 in Dalian. The first 108 locomotives used the 16V240ZJ engine. It took seven years to build all 108 locomotives of this type.
But the first ever is a permanent exhibition at the Beijing Railway Museum, and the second "Mao Zedong" is a permanent exhibition at the Fengtai Yard, Beijing Railway Bureau.
DF4A.
The DF4A used an improved engine, the 16V240ZJA. Production started in 1976 and lasted until 1984.
Manufacturers.
DF4s have been manufactured by several companies: