Importance of system integration in railway design

Like other elements of national infrastructure upon which the public relies, train services are taken for granted, and usually only come to mind when they don’t work properly.

Railways comprise many interactive systems, so there’s plenty of scope for problems to arise. For example, the rails that steer and support train wheels can also carry electrical currents which are part of the signalling system, and others which are part of the traction power system and which can have significantly different characteristics, including the ability to generate electro-magnetic interference. Apparatus for radio and telephonic voice communications, control, command and monitoring functions, fencing and drainage together with power, gas and water supplies can all vie for space on stations, depots, bridges, cuttings, embankments and tunnels. Data for customer information, CCTV, fire detection and intruder alarms can take up capacity on wide-area telecommunications networks. Many of these assets have to be designed so that they can remain operational when the railway or its electrical power supply is operating in a variety of degraded modes, such as during maintenance activities. The many types of rolling stock have to be compatible with the infrastructure and with each other, too.

Thus, each system has to be designed with not just its own functionality in mind, but also that of the other systems, and their interactions. Critically, human factors also have to be accounted for, to control the risk of operator error, and consideration has to be given to health and safety, environmental impact and sustainability in all phases of asset life. When modifications to existing railways are planned, constructability reviews account for the extra dimension of stage-works, so as to minimise the effects on train services.

The leading role in specifying railway works is invariably taken by the client, who can normally be considered to be an “informed client”. This means that the client cannot simply abdicate responsibility to its contractors, but has to use processes that assure the project’s delivery for an optimal whole-life cost.

One of the first things a client has to do is to formulate a procurement strategy. Clients may use their own, in-house project managers or supplement them with specialist firms, who usually have different risk-sharing and incentive profiles from designers and other contractors. Owing to the inter-active nature of railway systems, their procurement is sometimes packaged by scope, e.g. signalling and telecommunications, or by activity, e.g. design and construction. The client’s role is focal, as the relationships between contractors derive from their individual contracts with the client. Each of those contracts needs properly to reflect the way in which the client wishes the contractors to behave, not just with the client, but also with each other. Clients devise contracts which share risks and set incentives that best suit their business objectives, subject where applicable to regulatory requirements. Nevertheless, the identification of the party who is to manage each particular risk is an important step, although sometimes it is not practicable to do so fully until designs have been produced.

Safety assurance and validation techniques are deployed, involving neighbouring businesses where necessary, to ensure the mutual compatibility of the respective systems. Standards regimes are comprehensive but often address the level of performance to be achieved without specifying how the standards are to be delivered, because systems interfaces are dependent on the specific nature of each project, and commercial advantage can be gained by both the client and the successful tenderer if know-how is used to good effect. The principles to be adopted for systems integration need to support and be supported by the detailed practices of the participants: success is delivered by people and it depends on their ability to operate effectively both as individuals and as part of a team.

Commercial boundaries can detract from teamwork. Partnering is a concept which has been widely misunderstood, but when realistically implemented it can bring significant benefits. Partnering doesn’t mean that proper commercial discipline is unnecessary, or that partners have to avoid upsetting each other. On the contrary, partnering means that alignment of the interests of the parties and mutual understanding of their respective responsibilities and performance should give more visibility to issues that could become obstacles to joint success. If things do go awry, then well-drafted agreements and proper records will help to stave off a dispute or facilitate a cost-effective resolution.

Focussing on how people deliver systems integration in railway design will hopefully not only deliver good things such as being on time and on budget, making a profit and winning repeat business, but will also result in happy customers whose train services haven’t been delayed.

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