Sign T-1: traffic signals or sound signals

Appearance of the sign was based on Ordinance of the Ministers of Municipal Economy and Communication of December 2, 1970 on additional signs for tram and trolleybus drivers (M.P. 1971 nr 2 poz. 7), valid from January 12, 1971 to April 17, 1985. In 1985 it was replaced by sign used to the present day, by the Ordinance of Ministry of Administration and Industrial Economy of February 21, 1985 on additional signs and signals for tram and trolleybus drivers (Dz.U. 1985 nr 15 poz. 62)
Own work
Miko101