Class 434F 4-8-4T (1986)

Class 434F 3-Cylinder Compound General Purpose Tank Locomotive
Designed by Jochann Ketterik
Built in 1986 (under the auspices of Artur Gorote)
by RSR Works,
Bevice-Akohniçe, Ruhnia

Several times during the history of the RSR related locomotives have shared a common fate. So it was also with the 423Ds and 423Es. By the early 1980s their boilers were feeling (and showing) their age. Ketterik clearly felt that these engines had not yet had their day and decided to bring them into line with current practice. The most drastic aspect of the rebuild was the conversion to 3-cylinder compound drive. The outside cylinders retained their quartering and received low-pressure steam and a new, high-pressure inside cylinder was installed, its crank being set at 135° to each of the outside ones. All three cylinders drive the second coupled axle. The leading coupled axle is cranked to clear the inside connecting rod. Steam is fed saturated to the high-pressure cylinder and resuperheated for the low-pressure cylinders. In this way, an excessively high temperature of superheat is avoided, simplifying the lubrication of the high-pressure cylinder. In addition, the rebuild involved poppet valves, boxpok wheels and a new, tapered boiler, with a similar firebox to that used earlier on the 323FFs and 533BBs, the difference being the installation of a gas producer combustion system. All 83 of the engines still surviving in 1986 were rebuilt; work proceeded quite slowly, the last rebuilt locomotive emerging from the works in 1994. In the final analysis, not much was left of the original design except the mainframes (suitably modified) and the cabs, water tanks and coal bunkers.