All the electrical systems from the 13N remained unchanged, but the 105N abandoned the streamlined appearance of its predecessor for a more angular look.

These changes made the 105N significantly (approximately 1200 kg) lighter than the 13N and decreased the amount of raw materials used in production.

The first models lacked the ability to be connected to one another, and the placement of the electrical system caused problems with humidity.

In Gdańsk, Poznań, Szczecin,[1] and Warsaw[2] there are cabs rebuilt to the earliest version.

14 thyristor-based 105NT units were built in 1989, most got downgraded to the 105Na standard, with exception of #TT021 owned by MPK Kraków and #790 owned by Silesian Trams, which was upgraded between 2004 and 2006 to 105N-2K standard, and got rebuilt in 2016. the 105NT type was the developed version of the faulty 106N developed in back 1977 In 1995, on the basis of two 105N cabs, HCP in Poznań built a prototype of a three-module, partially low-floor tram, the Konstal/HCP 105N/2 but issues with reliability, coupled with availability of cheap second-hand rolling stock, caused the project to be abandoned.