Rail Systems: A Quick Summary
Posted by Richard Poulter on Friday, December 7, 2018
To many of us, rail engineering is a mystery, a corner of civil engineering that appears relatively straightforward on the surface but – in reality – requires in-depth knowledge of a range of activities. (Though you could say that applies to most areas of civil engineering and construction.) If you’ve always wondered what rail engineering is all about, here’s a brief overview.
Rail Track Design and Installation
The most obvious part of a rail engineer’s job is to design the rail track, but it’s more than just laying some rails and backfilling with ballast. The subgrade under the track has to be taken into account to give the train a dependable surface to travel on, and the right ballast specified. The sleeper density and quantity also need to be determined.
The geometry – or horizontal and vertical alignments – of the railway need to have large radii (horizontally) and be shallow enough (vertically) to ensure the rolling stock (the vehicles that use the railway) can safely travel on the track, while also having enough clearance between other tracks and obstructions. The speed of the trains and the stopping distance they require are other important factors. Add in a railway bridge or tunnel and the project gets even more complex.
Rail Electrification and Overhead Line Equipment
And that also assumes that the track isn’t electrified and overhead line equipment (OLE) aren’t required. With the move to more sustainable, eco-friendly transport, rail electrification is becoming a bigger focus for many rail engineers. Electrified railways need an assembly of masts, gantries and wires to power the electric trains, as well as substations every 40-60km along the route.
Approximately 400,000V of alternating current (AC) is taken from a power station, transmitted via a transformer into overhead transmission lines to the substations, which reduce the current to 25,000V. The contact wire – held safely overhead by the masts and gantries – then transmits the power to the train. Network Rail published a useful guide to rail electrification which explains the process simply. So, not only must rail engineers understand track design, they also need to understand electricity and how it is transmitted and safely used.
Train Control Systems and Signalling
While previously electrical control was done manually, there are now supervisory control and data acquisition (SCADA) control systems that can integrate electrical control into the rail operating centres. It can also provide a unified means of control for both the existing and electrified sections of the railway.
Railway signalling is a whole subfield of rail systems engineering, much like traffic lights are to highway engineering. Similarly, train signalling systems are used to detect and direct trains in order to prevent collisions. Railway lines are divided into sections referred to as blocks, with only one train being permitted to occupy a block at one time. Each block has its own set of signals located along the track (trackside).
However, traditional trackside signals are being replaced with more modern technology, such as communications-based train control (CBTC). This involves installing in-cab computer displays and control centre systems which provide information directly to the train driver. The benefit of these systems is that they allow trains to run closer together and to travel at their optimum speeds while maintaining safe braking distances.
Rail Systems Engineering and Assurance
With the number of disciplines and activities required in railway engineering, a unified approach is needed to join up the entire process – that is systems engineering (also sometimes called systems integration). The aim is to optimise project delivery, service reliability, environmental impact, cost efficiency, and capacity by looking at the rail delivery system as a whole.
Rail systems assurance, on the other hand, considers key management and engineering activities that can improve reliability, availability and mantainability (RAM). The aim of RAM is to minimise service disruptions caused by equipment failures, operator errors and maintenance.
What Opportunities Are Available?
The variety of specialisms in rail means that there are a wide range of jobs available in rail systems worldwide. Canada is in short supply of high-calibre rail design engineers, rail systems integration engineers and rail systems assurance engineers, and we are currently recruiting for a rail design manager based in Toronto or Vancouver. If you are looking for your next opportunity in rail systems engineering and fancy a challenge abroad, please get in touch.
About the Author
Construction Recruitment Director, Hong Kong
I am responsible for the recruitment business in Hong Kong, Asia, and the Middle East. I was a civil engineer and project manager for 15 years before becoming a construction industry recruitment consultant in 2004. I am based in the Hong Kong office and specialise in placing professionals in engineering, project management, planning, HSEQ and risk.
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