The Konstal 105Na are a class of Polish trams manufactured from 1979 to 1992 in workshops Konstal Chorzow, Poland. The meter-gauge version is designated as 805Na. As of 2016 they were still the most common trams in Poland.
Construction
105Na is unidirectional motor tramcar, equipped with four doors.[1]
It is a development of the earlier Konstal 105N. The main changes being a shift in the location of the electrical equipment from under the steps to the back wall of the driver's cabin, the introduction of a separate cabin for the driver, as well as the removal of the small windows under the front and side windscreens.[1] The most important change was the introduction of motor grouping, which reduced the energy consumption by 12%.[citation needed] During initial acceleration, the four motors are connected in series, whilst at higher speeds, two groups of motors are connected in parallel.[1]
While in service, the 105Na vehicles were the subject of various modifications and upgrades (including changes in the electrical system, new front plastic, change of the door opening mechanism, and even re-design, for Poznań, to the bidirectional Konstal 105NaDK). Almost all 105N cars in Poland have over time been modernised to the 105Na standard.