Polish manufacturers of rolling stock are known for their diversity in newly developed types of rolling stock. But they are also actively modernizing older types of Polish trains, so that they'll meet modern requirements again. A good example is the 6Dg diesel shunter, a product of Newag and based on the 30 years old SM42 diesel locomotive.

Now Lotos Kolej has received the first two of three 6Dg machines. The video shows one of the new machines shunting with two electrics in service of Lotos.

Various other Polish operators have 6Dg locomotives in their fleets. Examples are:
ISD Huta Częstochowa, PKP Cargo, PNUIK Kraków, Pol-Miedź Trans, KOLTAR Grupa Azoty, and Kolprem.