Rail surfacing and grinding
Tram rails are exposed to extreme loads, which sooner or later result in some kind of defect. The repair of tram rails belongs among those jobs which are very demanding in relation to precision as well as to punctual planning due to the necessity of traffic rerouting. Pražská strojírna a.s. has provided tram rail repair services since 1997, thus it has vast experience. References for the tram rails repaired by our company can be provided by our satisfied customers including DP Prague, DP Olomouc, DP Plzen, DP Most and Litvinov, DP Liberec, and DP Bratislava.
Rail surfacing – re-shaping of the rail
Side surfacing of track rails in radiuses with subsequent grinding into a required profile represents the most cost-effective way of prolonging the rail lifespan. Quality surfacing postpones the necessity for the greatly more expensive and complicated rail exchange.
Our process of profile renewal by surfacing is based on using a Cr18Ni8Mn6 chemical composition wire (additional material), which complies with the plasticity requirement of individual sections of the surfaced rail system. We achieve a 30% of difference in the hardness of the overlay in comparison with the base material. The mechanical properties of the overlay can be further enhanced by inserting an additional layer with a higher manganese content, which increases the abrasion resistance by approximately 30%. The job is performed by qualified crews, which are regularly examined by a welding authority. Thorough preparation is a matter of course – the surface is cleaned by grinding and preheated at a low temperature. The rail grinding tools are effective enough to perfectly grind the overlays into the required shape.
Pražská strojírna a.s. currently owns three automatic surfacing flux units with an individual capacity of 20m grinded overlay per shift, respectively 30m per 12-hour extended shift.
Grinding of corrugated rails
Rail corrugation is often an underestimated factor. Firstly, it causes an increased level of noise, which is a common and justified subject of local complaint. Aside from this it always leads to serious destruction of the entire track including the track bed. The dynamic shocks are relayed to the surrounding buildings, resulting in their subsequent static damage.
In order to deal with rail corrugation, Pražská strojírna a.s. possesses two grinders, each of which is capable of grinding approximately 400 m per shift. The machines work on the principle of rotating grinding drums. These machines have proven themselves in Prague over the course of many years. DP Prague runs tram transportation around the clock, and incidental exclusions are undesirable. Thanks to their design our grinding machines are suitable for use during tram operation, as making the way for tram coming can be done almost instantly.
In the case of a necessity of greater performance, we are able to provide a machine that is able to grind 2,000 m of rails per shift. This machine, however, requires tram line exclusion.