Globally, the market for CNC machined parts is growing rapidly at 6.8% per year and is estimated to reach $100.9 billion by 2025*. The rail industry will make up a large proportion of that market.
In Australia, railway equipment manufacturers currently purchase nearly $2 billion of Australian-made inputs from manufacturers of metal products and electrical equipment**.
CNC machining has seen a lot of innovation in recent years which has positively impacted the rail industry. The growth of 5-axis technology has allowed parts with complex geometry to be machined that were previously impossible with 3-axis CNC machines.
5-axis technology and large CNC machinery capable of milling, turning and boring large precision parts has been great news for the rail industry. The rail industry requires a large number of specialist precision parts manufactured to fine tolerances, which has led to optimised CNC machining practices.
In this article, we’ll examine how the rail industry uses CNC machined parts across the rail network and how they are manufactured.
The Benefits of CNC Machining for the Rail Industry
Using CNC machines to fabricate parts and components has the following benefits:
Large quantities of specialist parts can be machined accurately and quickly.
Complex geometry can be created that isn’t possible with manual machining.
Uniformity and consistency of the finished product.
More efficient and lower costs overall compared to traditional manual machining.
Types of CNC Machined Parts for the Rail Industry
Bogies and wheels
Bogies are the 4 or 6-wheeled trucks that support rail vehicles. Over the years, bogie design has changed from a basic construction to an intricate assembly of complex, precision parts, especially on high-speed tilting rolling stock for instance.
Most modern large, high-strength steel alloy axles are CNC machined in vertical pendulum mills. These floor type mills allow two sets of bogie axles to be machined and prepared simultaneously. Milling bogies in a vertically clamped position ensures that heat transference is reduced, decreasing the risk of metal deformation. This is vital for rolling stock manufacturers, as design tolerances are very tight.
Train wheels benefit from CNC machines with angular heads to accurately shape the flanges.
Other CNC machined parts that make up the bogie units are smaller components such as the springs and fixings in the suspension system, as well as caliper pins, brushes and specialist bolts.
The types of rolling stock that require CNC machined bogies and wheels are most commonly high-speed trains, locomotive wagons, trailers, underground rail carriages and trams.
The rail network comprises of thousands of specialist small components and parts. These components are intricately designed with complex geometry and manufactured in CNC lathes and turning machines.
Small CNC machined parts and components include relays for signalling systems, rail fixings and point mechanisms.
Composite materials for train carriages
CNC machines are capable of working with a variety of materials including synthetic resins and plastics or composites. Modern train carriages use CNC machined composite materials for the body and for internal fixtures.
Other materials used for rail and train components include mild steel, aluminium, stainless steel, cast iron and brass.
Design and engineering of CNC machined parts
3D models for CNC machining are created in software such as Autodesk Fusion 360. Many machine shops offer a design and engineering service to build parts from start to finish. This includes creating prototypes to ensure that specifications are met.
A full design and engineering service is ideal for the rail industry as the technology advances quickly and new components are needed often. The flexibility and versatility of CNC machining means that prototype assemblies can be designed, made and trialled quickly and efficiently.
Creating CNC Machined Parts for the Rail Industry
Industry 4.0, also known as the 4th industrial revolution, has led to highly integrated manufacturing processes. CNC machining is no exception. It’s already possible to send a design specification, or basic geometry sketches to a machine shop that will be able to quickly create a 3D model. CAM software creates the code to operate the CNC machine which can then produce a prototype. Once the design has been approved the parts can be rapidly machined.
*Source: Transparency Market Research
** Source: Submission to Senate Reference Committee on Rail Industry 2017
Challenge Engineering is an ISO 9001:2015 certified CNC machining company based in Sydney, Australia. We manufacture parts for large rail companies. To find out more visit www.challengecnc.com.au.