New trams had a construction and electric schemes very different from locally produced cars. Doors of motor car were opened and shut with compressed air (by the way, doors of non-motor car B-54 were not automatic and had to be closed manually). Tram had rail breaks for emergency stopping which became standard for trams in Tallinn (true enough, rail breaks had to be uninstalled in the beginning because of state of tracks). On the photo you can see that the tram had doors on both sides, also, motor car had driver cabin at both end. So there was no need for circles at the ends of the lines. Later on when there were circles built at every terminus left doors were closed and back cabins demounted. Additional installations got from there were used for modernizing local cars.

If you look carefully at the second picture you can see that trolley lines in Old Lasnamägi (that was being built then) were attached to traditional carrying posts which are now replaced with suspension system.