EMD - 645 & 710 Engines
The EMD 645 series of diesel engines were designed and manufactured by the Electro-Motive Division of General Motors, primarily for use within rail traction and marine propulsion industries. The ‘two-stroke’ engines have a stroke of 254mm and a bore of 230mm, key design features of the engines are the cylinder units or ‘power pack assemblies’ consisting of a cylinder head, cylinder liner, piston, piston carrier and piston rod which can be individually replaced relatively easily and quickly. The connecting rods use a simple system of fork rods on one bank of cylinders and blade rods on the other.
All 645 engines utilize forced induction, with either a Roots blower or a turbocharger. The turbocharger works using EMD's unique design that incorporates a gear train with an over-running clutch to drive the compressor rotor during low engine speed. At higher engine speeds, increased exhaust gas pressure is sufficient to drive the turbine and the clutch disengages, turning the turbo-compressor system into a true turbocharger.
The EMD 710 series replaced the earlier EMD 645 in 1985, with an increased stroke of 279 mm and turbocharger ‘only’ build. Since its introduction, EMD has continually upgraded the 710G engine, the power output has subsequently increased from the 3,800BHP (16-710G3A) to 4,500BHP (16-710G3C-T2)
The engine is made in V8, V12, V16, and V20 configurations, although most current locomotive production is the V16 engine, whereas most current marine and stationary engine operation use the V20 engine.
EMD diesel powered locomotives widely used on UK railways are Class 57, Class 59 and Class 66, operated by companies such as DB Schenker, Colas Rail Ltd, Freightliner, GB Railfreight, DRS and Network Rail.