Background and overview
In 2017, JR Freight developed class DD200-900 pre-production type of Bo-Bo wheel arrangement diesel-electric locomotive for use on freight services over non-electrified lines, and also for shunting duties at freight terminals, in order to replace superannuated DE10 diesel-hydraulic locomotives. Its total mass is limited to 58.8t to realize low axle load at 14.7t for use on lower class track. Maximum service speed is 110km/h to prevent non-revenue mode from operating at limited lower speed.

Car body
DD200-900 features 15.9-meter-long to reduce the total mass. The vehicle design fundamentally consists of low hood for good visibility in both directions, fitted with a heat exchanger, a prime mover, and an electrical generator at the front, a steeple cab at the centre, and a traction system, and an auxiliary power supply at the rear. An air compressor is fitted under the cab. a motor driven air compressor and a fuel tank is fitted under the frame. Noise absorbing materials are fitted inside the access doors of front hood to reduce the noise pollution.

Bogies
Bogies, FDT103, are bolster-less type with air spring and the journal box supporting system adopts axle arm type. The diameter of wheels is 910mm. DD200-900 adopts nose suspended drive.

Traction unit and auxiliary equipments
DD200-900 is equipped with single water-cooled four-cycle V12-cylinder diesel engine, FDML30Z of Komatsu Ltd, with a power output of 895kW. A prime mover is connected to 3 phase brush-less synchronous generator with a power output of 1112kVA, creating electricity that powers electric traction motors. Nose-suspended traction motors, FMT102, with a power output of 160kW are controlled by the variable frequency drive traction system on axle basis, featuring Silicon carbide (SiC) MOSFET and Insulated-Gate Bipolar Transistor (IGBT). It is also equipped with a duplex auxiliary power supply with a power output of 80kVA featuring a silicon carbide-based MOSFET. The brake system is the electric command brake.

Operations
This was scheduled to undergo testing and evaluation in Ishinomaki line freight operations in Sendai area to obtain data to be used in the design of the full-production locomotives. After the full-production locomotives, DD200-0, were deliverd, DD200-901 locomotive is operated along with DD200-0 locomotives.