CRRC Tangshan has completed pre-delivery testing of a variable configuration electric multiple-unit, which is designed to be formed of two power cars and up to 16 single or double-deck coaches. The train has been designed to enable operators to configure train lengths in response to changes in passenger demand, unlike current trainsets which are in fixed-formation eight or 16-car sets. 

CRRC said the EMU was 'the Transformer of EMUs', and compared altering the train length to 'playing with Lego bricks'. Development of an EMU where individual vehicles can be added or removed required CRRC to develop technologies for integrating traction power supplies, networking the control systems and providing suitable inter-vehicle couplers.

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