It is one of the most powerful steam locomotives in Bulgaria, one of the largest tank engines in Europe, as well as the first and, in fact, the only ones in the country to feature two flangeless wheelsets in its running gear. A unique achievement in locomotive engineering.
All of the Class 46.00 locomotives, each of which was simply known as “Baba Metsa” to the staff in the Sofia area — a nickname earned due to their compact design, relatively low design speed, and great power—tirelessly hauled heavy freight trains through Vladaya and Razmenna until they were replaced by diesel traction between 1967 and 1969. Steam locomotive No. 46.03 is equipped with the “Zwilling” system.
During its service, the revolutionary poet Nikola Yovkov Vaptsarov served on this locomotive for the longest cumulative period while working as a stoker at the Sofia depot. It would be difficult to find another railway administration that used such steam locomotives for 50 years without interruption under regular operating conditions. The service life of steam locomotive No. 46.03 was approximately 44 years.
It was restored to working order in 2015 to operate as a tourist attraction.
