The Railway System
The railway is a transport system that allows trains to move people or materials from one place to another. It has developed over time to become a system that involves many different engineering disciplines. All the different parts of the system must work together to allow trains to move from one point to another safely and efficiently.
The PWay Engineer focuses on Track Engineering however, it is important to understand the whole system and other engineering disciplines as there are many overlaps and interfaces. Below is a summary of the major engineering disciplines you may come across on the railway. This is not an exhaustive list but should give you an idea of the variety of disciplines involved.
Geotechnical and Civil
Starting from the ground up, firm foundations are key. We want the railway to be laid on firm foundations. When we have trains weighing hundreds of tonnes carrying people and goods at speeds up to or over 100mph ensuring the railway is stable is key. It is also ideal that the railway is as flat as possible, so we have cuttings through hills and embankments over low ground to also consider. Geotechnical engineers are the engineers that concern themselves with all these elements of the railway infrastructure
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To get across roads and rivers, we need bridges. To go through ridgelines and hills, we need tunnels. To allow passengers to embark and disembark trains we need stations. These are some of the areas civil engineers get involved. Some of the most recognisable and noticeable parts of the railway are its bridges and stations. Think of the Glenfinnan Viaduct and Kings Cross Station as seen in the Harry Potter films.
Track
The track structure starts from the formation and geotextiles that along with the ballast form the track bed. The track bed is designed to do a number of things including support the track, distribute the load of trains, drain away water and restrain the sleepers from lateral movement.
On the track bed, and surrounded by top stone ballast, sits the sleepers. These house the rails, holding them to the correct gauge or distance apart. Then we come to the rails, the interface with the wheels. Track can be in the form of plain line, two bits of rail running parallel from A to B or Switches and Crossings, where trains crossover lines. Another key consideration is the geometry of the track, its curves, straights and cants.
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The design construction and maintenance of all this is the domain of track engineers.
Signalling
The railway traffic lights and control systems. In a world where we want to run multiple trains on the railway lines, use junctions to allow different destinations or routes and ensure all this is done safely, a signalling system is needed.
Through systems such as track circuits or axel counters, signaller can see where trains are on the network. Signallers can move points to allow trains to move to different tracks and take different routes. Signals showing aspects (colours) tell drivers to stop, caution or go. Level crossings allow roads and rails lines to cross where a bridge cannot or has not been constructed.
Signalling systems must be designed so that if they fail in anyway, they do so in a safe way without putting anyone at risk.
Electrification and Plant
From a simple light on a buffer stop right up to the trains themselves (unless of course they are diesel powered), all need electricity to function. The railway network is one of, if not the biggest single user of electricity in the UK.
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A substantial proportion of this goes toward powering the trains. This is done via Over Head Line (OLE) equipment or via conductor rails. Which system is used is normally a geographical question, with the South East are using conductor rails and the rest of the UK using OLE.
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Signalling systems as well as the motors used to swing points are just two examples of the range of railway equipment that also needs to be supplied with power, often in remote locations. This leads to a large volume of cables that also must be managed.