Like that earlier Series, it has a microprocessor-equipped engine control unit, and a modular system of construction of the vehicle body.

All models of the Dash 9 Series are powered by a 16-cylinder, turbocharged, GE 7FDL 4-stroke diesel engine, with electronic fuel injection and split cooling.

Dash 9 Series locomotives also ride on HiAd (high adhesion) trucks, with low weight transfer characteristics and microprocessor controlled wheelslip.

All were built with rooftop-mounted air conditioners which gives them a rather unusual and distinctive look - and were quickly coined "top hats" by the railfan community.

[3] Besides, standard cab GE's had become more expensive by the mid-1990s, since they were now considered optional equipment by the builder, and thus priced as such, and when a carrier is purchasing one or two hundred units of a particular model at a time, even a slight extra price for a customized cab can add hundreds of thousands of dollars to the cost of a locomotive order.

The C44-9W model was in production between 1993 and 2004 with 53 pre-production units being built for CSX with an extended Dash 8 carbody and trucks a couple years earlier.

Substantial orders for this model were also received from operators in Australia and Brazil, in the latter case for 1,600 mm (5 ft 3 in) broad gauge versions.

It is used on the Qingzang Railway, which connects Xining, Qinghai Province, to Lhasa, Tibet Autonomous Region, in the People's Republic of China.