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Rail control room integration: risk and reward

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Railway Control room integration can be an emotive topic.

John Cranley, Expertise Leader - Rail & rail systems, shares his experiences and lessons learned from these often complex projects over his 20 year career. It’s an area that’s been close to his heart for the last 20 years.

My first real exposure to integrating control room functionality came about during my involvement with the Central Line Upgrade project being undertaken by London Underground (LUL) during the early 1990s.

A decision had been made by LUL operations staff to devolve the control of the DC1 circuit breakers from the power control centre at Long Acre and transfer them to the new line control centre at White City.

There were numerous, technical, and operational issues surrounding this decision, one of which was that this was yet another disparate system for the new ‘swish’ control room and associated equipment room to house, with different operator workstations to the train control system and the line control systems, thus detracting from the clean ergonomic environment the engineers and architects were trying to create.

Alternate Options

As engineers we looked around for alternative options and that’s when I came upon integrating railway control room functionality. Sadly the timeframes for the project did not permit proceeding with this developing technology. Therein lies one of the major concerns for the opponents of functional integration, risk. It is key to make the decision to integrate early in a project to mitigate risk both to programme delivery and the budget.

From a control room hardware perspective, integrating control room functionality essentially means providing a common Human Machine Interface (HMI) to all operators in the control room regardless of the tasks that operator is required to undertake.  The functions required by the operators to perform their jobs then become available to them when they log on via an ‘Area of Responsibility’ (AoR).

There are then two ways the functions can be presented to the HMI:

  1. Through a single (dual redundant) system, normally from a single supplier,
  2. Through a server (dual redundant) which integrates a number of systems from different suppliers.

Some of the immediate benefits of functional integration include:

  1. Common ‘look and feel’ of the workstations. This makes it easier for staff to be trained in new tasks due to familiarity with system, allowing authorities greater flexibility with their operations.
  2. An operator using his/her AoR has the ability to logon at any workstation if his/her’s fails. If critical workstations are lost due to a failure, these functions are then immediately available to the operator at adjacent workstations, which handles non-critical functions by the operator logging on using the assigned AoR. This minimises downtime and potentially avoids rail shutdowns thus providing greater flexibility and less risk to operations.
  3. Lower spares holding as a single workstation type is used for all functions.
  4. Ability to recover from a ‘control room disaster’. Dependant on the communications network, all functions can be made available at any workstation. So if the main control room has to be evacuated, station management workstations can be used for control room functions if required. This creates a more ‘available’ system, without unnecessary duplication of hardware, only ever used in a failure.
  5. A cleaner, more organised appearance to the control room, therefore creating and supporting the image the authority is in control to visitors, which could include the media. This can be particularly important in the event of a crisis situation where the authority may want to give control room access to the media to show them they have the situation under control.

Dependent on the rail authority, some of the functions available in the control room may have Safety Integrity Level (SIL) criteria associated with them.

For example the operation of traction supply circuit breakers in a number of authorities is a SIL 2 function and other functions such as public address announcements to surface stations have no SIL requirements.

A concern with a single supplier system is that the customer maybe paying for the additional software control measure which is required to be put in place for a SIL 2 system and will also need to undertaken for the non SIL functionality i.e. an increased cost and possible increased project duration to the customer.

Melbourne, AustraliaLikewise for the multiple supplier solution a concern is it introduces another level of complexity and therefore risk, with the only immediately perceived benefit a common ‘look and feel’ HMI for the operators.

There are other issues associated with both options above, which I have heard discussed over the years, and essentially they all revolve around complexity of the software, which creates a greater risk to the delivery program, and the budget of these projects.

However, there are additional benefits to integrating control room functions, which may not appear obvious up front.

For example decision support systems helping operators to analyse network problems quicker than what might be achieved manually. With all functions coming through one system, event associations can be pre-programmed into the system by maintenance and operations staff, using ‘operator friendly’ interfaces.

Dependent on the filtering mechanisms one or more solutions can be presented to the operator to resolve the network incident quickly. As confidence grows within the operations staff on the accuracy of the solutions presented, control sequences can be implemented on multiple control actions, further accelerating the resolution of the incident.

Clearly, the debate is likely to go on for many years to come on the pros and cons of functional integration of control rooms. One size does not fit all, and each authority needs to decide on the perceived benefits or not to their organisation.

What I have learnt over the years though, if an integrated control room environment is not considered at an early enough phase of any project, then the decision is usually already made for the authority, with the risk to program and costs being too high.

Like all good projects, the first step is a clear and agreed set of user requirements. From these user requirements consideration should then be given as to whether integrated control room functionality best meets the client’s needs.

If this is done early enough in the project cycle the integration risks can be mitigated, hopefully leading to the realisation of effective control room integration with the rail authority reaping the benefit for years to come.

1 London Undergrounds traction supply system is a 630v DC system fed from an 11kv/22kv AC supply reticulated around the network.
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