The term reconstruction locomotive (abbreviation: Rekolok ) was introduced in 1957 at the Deutsche Reichsbahn in the GDR.

The term is used for series of steam locomotives of the Deutsche Reichsbahn undergoing significant renovation work to improve performance and to adapt to the fuel situation in the GDR ( lack of the Lokomotivfeuerung suitable coal ) and to eliminate design errors and war-related " Entfeinerungen " were made. At the same time repairs were carried out. Repairs included at least also the installation of a new high-performance steam generator. A characteristic feature of this Rekoloks is accordingly the combustion chamber boiler with the square mixing box in front of the chimney. Individual series, which had not been designed according to the principles of unity locomotives (BR 58.30 and 39) were given instead of the new cab end walls always required by the boiler change completely newly built unit cabs. Likewise wheelsets with different wheel diameters were replaced by those of the standard type (especially in the former Saxon 19.0 ). The worn- cast cylinder blocks were replaced partially by cylinders of welded construction. In contrast to the reconstruction program of the German Federal Railways, the new boilers were not adapted to the respective models of engine, but the mounting points of the new locomotives boilers. The thus obtained free interchangeability of the steam generator -bought one by partial sweeping changes to the locomotive frame. After the conversions most Rekobaureihen left the workshops with a completely new look. The most striking examples of the series are to name 01.5 and 58.30.

Basically, only selected models of engine were reconstructed, which were not dispensable in operational service and of whom you have expected a long period of use. Donor vehicles for it were mostly locomotives recent model years or production groups, which were due to be worked up anyway.

As the first car freight train locomotive 50 3501 left on November 12, 1957, the Raw Stendal, which she had been fed as 50 380. The first Reko -50, now known as 50.35, said one to the Bw Güsten. Last Rekolok was the 52 8200 which was on 23 December 1967 in operation, the Rekoprogramm was initially considered terminated. 1968, called for the state and party leadership of the GDR, the Reichsbahn on a strategic reserve of 45 express locomotives of Class 03 ( 18 t mean knoll salmon driving mass ) to create. From 1969 to 1972, in Raw Meiningen not only the required 45, but even 52 locomotives of this series with only a few years old Rekokesseln the hitherto largely discarded BR 22 (formerly BR 39, Prussian P 10 ) has been fitted. The Rekolomotiven the BR 58.30 were due to her age and the very extensive repair and labor needs of donor vessels, the most expensive redesigns of the entire program.

Machines were reconstructed from the following standard gauge steam locomotive series at Deutsche Reichsbahn and assigned a new series or sub- series:

And as individual vehicles for trial operation and partly as a test vehicle:

Overall charge of the reconstruction program, the VES -M Halle in Halle was (Saale ).