Since 2007, die­sel loco­mo­ti­ves type 311D and 311Da (adap­ted to tra­vel­ling along the 1520 mm wide track) have been moder­ni­sed as a result of coope­ra­tion between NEWAG SA and the Ame­ri­can Gene­ral Elec­tric (GE).

The cho­ice of NEWAG as the coope­ra­tion part­ner on the Euro­pean mar­ket in the scope of moder­ni­za­tion of loco­mo­ti­ves was pre­ce­ded by three-year nego­tia­tions and a posi­tive veri­fi­ca­tion of the com­pany from Nowy Sącz by the Ame­ri­can part­ner. Since 2007, NEWAG SA has con­duc­ted seve­ral dozen moder­ni­za­tions of this type.

The 311D/311Da type fre­ight loco­mo­tive ori­gi­na­ted as a result of a com­plete over­haul of the Rus­sian M62-type loco­mo­tive known on the Polish mar­ket under desi­gna­tion ST44.

The key scope of the loco­mo­tive moder­ni­za­tion was moun­ting the inte­gra­ted drive unit (engine, gene­ra­tor, com­pres­sor, cooling sys­tem) which is deli­ve­red fully assem­bled by Gene­ral Elec­tric. The chas­sis is the ST44 loco­mo­tive con­struc­tion, with a pro­ven track record, which under­goes the com­plete over­haul. The ori­gi­nal Rus­sian type ED 118 trac­tion engi­nes were used, whose insu­la­tion class has been incre­ased to class H. The loco­mo­tive has the Oer­li­kon pneu­ma­tic brake sys­tem. More­over, it is equ­ip­ped with new, ergo­no­mic driver’s cabs ensu­ring high wor­king com­fort. Modern micro­pro­ces­sor loco­mo­tive con­trol ena­bles the maxi­mum explo­ita­tion of its trac­tion features.