Road Number 01 512 with Boxpok Wheels
At the start of the Sixties, the GDR's German State Railroad put 35 units of the class 01 through an extensive reconstruction program. Initially only the installation of a welded replacement boiler was planned on the locomotives selected, but the condition of these units imposed extensive rebuilding that resulted in new locomotives in many areas of the parts overhauled. The maintenance facility in Halberstadt delivered the replacement boilers, and the maintenance facility in Meiningen installed them. The boiler was positioned higher in the rebuilding and a continuous dome streamlining adorned the crown of the boiler. The cabs were replaced by a new welded version. The locomotives rebuilt in this manner had hardly anything in common with their original appearance. Therefore, these units were given the new class designation 01.5 after the rebuilding. The locomotives starting with road number 01 519 (rebuilt in 1964) were equipped with oil main firing. The rest of the units were retrofitted with this in 1965/66. Only six locomotives kept coal firing. Twelve units (road numbers 01 502-504, 507-513, 517, and 518) were temporarily equipped with Boxpok wheels that were replaced at the latest by 1976 with reinforced spoked wheels. Road number 01 504 ran in the beginning with a flat Giesl ejector. In addition, all of the units had a tapered smoke box door without a central locking device after the rebuilding program. With the introduction of computer-generated numbering, the coal-fired units became the class 01.15 and the oil-fired units were designated by the DR as the class 01.05.
After being rebuilt, the locomotives were used in the DR's heavy express service from Berlin-East Station (coal-fired locomotives) as well as from the Wittenberge and Erfurt districts. By the Seventies, they reached the West German turn-around points of Bebra and Hamburg-Altona in regularly scheduled Interzone service. In 1982, the career of the probably most successful design of the class 01 reached an end in the Saale Valley. Five units of the class 01.5 remain preserved and thunder along the rails – as along as operational – in East and West even after the reunification.