Dormer Pramet has supported the railway segment for many years with a wide range of cutting tools for both production and maintenance. Tomáš Hantek of Dormer Pramet investigates the applications cutting tools can support, such as the machining of rail switches and profiles, wheel sets, base plates and coupling mechanisms.

With a year on year increase of 2.6%, the railway industry is enjoying sustainable growth and is expected to be worth more than $280bn by 2020. An increasing demand for passenger and freight rail services is seeing a rapid growth in infrastructure investment around the world. Metalworking provides an invaluable role in the maintenance, repair and manufacture of numerous railway applications, including track, wheels and wagon parts.

Rail switches and profiles

An important element in any rail infrastructure is the machining of rail switches and crossings – the moveable sections that guide trains from one track to another. They have an especially limited lifespan, which can vary depending on numerous conditions, such as the level of usage and the surrounding environment.

A railroad switch, for example, created from new material has a standard guarantee of five years. If the switch is made from an applied material or has gone through a process of regeneration or necessary treatment (such as rubbing down or parts exchange), this lowers its guaranteed time to two years.

To ensure the reliability and safety of the switches, they must be updated regularly to remain fully operational. However, this alone is a huge undertaking. For example, in the Czech Republic, which has one of the most extensive rail networks in Europe with 9,000km of track and more than 25,000 switches. Dormer Pramet work with many leading manufacturers to offer both standard and custom tools to produce new railway switches, as well as the renovation of existing ones.

Tools for other switch parts (such as sliding chairs and switch rods) offer several advantages including durability, insert edge stability, shape precision and a rigid solution. Dormer Pramet’s assortment encompasses train and tram switches for all major rail profiles. The 60E1 and 60E2 rail profiles, for example, are the most common, especially in Europe. The type T section rail (flat bottom rails) is suitable for medium and heavy load traffic.

Wheel set machining

In new wheel set machining, most parts are manufactured from forged pieces. A major focus is that tools maximise process reliability and support a high-quality finish.

The production of new wheels, particularly roughing and finishing operations, can be completed with Dormer Pramet’s standard assortment of RCMX inserts. Numerous sizes, grades and chip breakers provide options for every workpiece material and cutting condition. As well as the manufacture of new wheels, there is a continuous need for wheel reprofiling through a wide assortment of machining centers from various manufacturers.

Dormer Pramet’s range of holders are suitable for some of the market-leading manufacturers, including Hegenscheidt-MFD and Rafamet machines. Since 1950, Hegenscheidt-MFD has installed more than 2,000 wheel set reprofiling machines around the world. Both companies use special-purpose wheel lathes for railways, metro, tram, and other light-rail transit systems, along with heavy-duty single and double-column vertical turning lathes, large bridge-type milling machines, horizontal lathes and special machines.

Dormer Pramet’s historical co-operation with machine producers and rail repair services has enabled the company to develop a wide range of standard and custom solutions for increasing productivity and reducing costs typically associated with these processes. This means that the renovation of railway and tramway wheels can be achieved with their standard assortment of inserts (LNMX, SNMX, CNMX), grades and chip breakers. Also, it offers a range of cartridges with pocket protection, allowing for a comprehensive and versatile solution for depth of cuts between 1.0mm and 16.0mm.

A Dormer Pramet customer in Ukraine, for example, required support with the reprofiling of railway wheels made of steel with a high hardness of 450-615HB. The LNMX30 insert with RF chip breaker and T9315 grade achieved a high level of durability and was significantly more productive than an equivalent supplier, machining 12 wheels compared to the competitor’s five.

Another success was with a specific machine builder for wheel set reprofiling in Poland. The customer wanted to resolve a chip breaking issue when machining hardened steel 800-900mpa. Once again, the LNMX30 insert was used, this time with the TF chip breaker and T5315 grade. This combination achieved 50% longer tool life compared to competitors, but also significantly improved chip breaking on the perpendicular surface.

Dormer Pramet’s T5315 grade is a versatile option designed for turning grey and ductile cast iron, as well as various steels, including hardened steel. It is suitable for roughing and finishing with medium-to-high cutting speeds and capable of both continuous and interrupted cut. This makes it a very versatile option in challenging machining conditions.

Base plates and coupling machining

Another area of activity is the machining of bearing or base plates – the connecting element which ensures the rail is attached to the railway tie or sleeper. This operation requires profile milling of this part where customers demand high productivity, while at the same time, respecting specific production limitations and materials. Milling cutters and drills are ideally suited to base plates production.

Finally, a coupling or coupler is a mechanism for connecting rolling stock to a train. The design of the coupler is standard, and almost as important as the track gauge. It needs to offer flexibility and convenience for all rolling stock to be coupled together. The equipment that connects the couplings to the rolling stock is known as the draft gear or draw gear.

The manufacture of couplers is an example of the type of niche cutting tools available to wagon producers from Dormer Pramet. Its many years of experience has resulted in various levels of support for the manufacture of axle boxes, center plates, bogie frames and fenders. Dormer Pramet’s approach, of systematically working in partnership with producers of these parts has allowed them to further refine and develop their cutting tool offer.

Tomáš Hantek is International Application Manager for Railway at Dormer Pramet, with customers ranging from state-owned companies to private rail operators.