Given the capacity issues facing the UK’s railways, with many services running at or near full capacity during peak periods, the upgrade of London Underground’s Victoria line is a perfect example of what can be achieved – working within the constraints of existing infrastructure.
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Following the completion of the two-year upgrade programme, from May 2017, trains have been pulling into the Victoria line’s stations every 100 seconds during peak hours, with 3,000 extra passengers able to travel every hour during these periods. This 36 trains per hour operation makes it the UK’s highest frequency metro line – and one of the highest frequency lines in the world.
Of course, achieving this performance milestone is one thing, but the key to long-term success is maintaining reliability, a requirement which was central to the Victoria line’s two major upgrade programmes, with exhaustive planning, testing and simulation undertaken to effectively “destruction test” the system in a laboratory environment.
Working in collaboration with the software supplier, engineering and operations testing teams were tasked with trying to break the system. If they succeeded, the scenario that caused a failure was carefully examined and the probability of it occurring in an operational environment determined. If there was 0% chance of this, no further action was required, but if there was any possibility, a solution was developed. This work gave the delivery team enormous confidence during the installation and operational phases.
With ongoing maintenance, there is clearly a need to balance the risk and reward of different approaches. At one extreme is the “fix it when it breaks” option – but this is expensive, disruptive and the least safe option. The other extreme is to have regular planned maintenance – however, this can be wasteful in time and resource if maintenance is unnecessary.
The panacea of maintenance, therefore, is condition-monitoring, whereby maintenance is undertaken only when required. As the panacea, it is of course the most difficult to achieve, but given the wealth of data we now collect from the control centre, on-board trains and the infrastructure, it has become a realistic option.
Reliability, though, is not just a function of the infrastructure’s performance, with Transport for London estimating that around 60% of lost customer hours are caused by human factors: for example people falling ill, or luggage trapped in doors. Planning for these apparently random events is more difficult, but the Victoria line upgrade work enabled short periods of operation at 38 trains per hour and in some circumstances even 39 trains, enabling the operator to return to the timetable quickly and efficiently.
Finally, we are seeing the Victoria line starting to change human behaviour on the Underground – particularly people running for trains and risking getting trapped in doors to catch one.
The regularity of the service means people now know they do not have to rush, because as one train departs, the next one is less than two minutes away.
● Ian Jones is key account manager at Siemens Rail Automation UK
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