First performed in December 2012, rotational planing has become an established technology for eliminating rolling contact fatigue and treating new rails in turnouts. Meanwhile two D-HOB 2500 rotational planers are operating in the entire DB network on tracks designed for speeds of as much as 300 km/h.
Description of the machine
The D-Hob 2500 is a conventional design vehicle comprising two bogies with two-axles each and close couplers. Vehicle clearance, axle loads and driving power were designed to allow working on the railway network of Deutsche Bahn (DB) as well as on various metro networks. The rotational planing machine is complemented by a control module and a chip module.
Mode of operation
Rotational planing combines milling and planing. The individual tools, that can be arranged in groups, perform a rotational movement that is superimposed by a short-time uniform movement parallel to the running surface of the rail. The target transverse profile of the rail head can be continuously changed during the rotational planing process, and these changes can be made independently for each rail. Thanks to this feature, mobile treatment of turnouts has become possible for the first time. The chips are sucked off immediately at the rotational planing tool and are conveyed into the chip container.
Scope of application and performance
Rotational planing offers decisive advantages over the grinding of rails in turnouts using rotating wheels. Metal removal of up to 2.5 mm per pass, measured at the centre of the rail, ensure that defects due to rolling contact fatigue can be safely eliminated. Where grinders need 10, 20 or even more passes, the rotational planer mostly achieves the desired result in a single pass. The machine works free of sparks and dust and the tools do not interfere with the required clearance. Covering pawl locks or switch rollers as well as cleaning after the completion of the treatment are no longer necessary. Both aspects save time and make rotational planing a most effective technology for the treatment of turnouts.