A world first for iPad

With 1.34 billion passengers a year, the Tube Is an intrinsic part of London life. Any disruptions, however small, to this essential service can cause a ripple effect that is felt not just on the network, but across the city itself.

Examples of this can be seen in surprising places. Take brake testing. Each time a Tube train is suspected of faulty brakes, it is removed from service to be tested. This is because, in order to see if brakes are working as intended, the existing testing technology required the train to be brought to a complete stop. The Underground’s tight schedule means if the train were left in service during this process, severe delays would occur across the line.

But what if the train’s brakes turn out to be working just fine?

Removing a train from service has still proved disruptive to passengers, and incurred costs for TfL. In one year we analyzed, over a quarter of Tube trains removed for testing on just three Underground lines were actually found to be fault-free. Scale this up across all lines, and the impact to both engineering time and lost passenger hours becomes a sizeable problem.

Since 2014, we have been working with Transport for London (TfL) to find leaner, more efficient ways of working, with the help of mobile technology.

The inefficiencies within the existing brake testing process made it a prime candidate for the program. Our joint teams began with a bold hypothesis: Could the iPad’s built-in sensors — the ones that can measure speed, pitch, roll and yaw — match the accuracy of existing testing methods?

And, if so, could an iPad be used on a train in service, thereby reducing the costly need to remove it?

Over the course of just five days, our engineering team conducted a technical proof of concept that demonstrably proved the iPad was up to the task.

The successful, quickfire experiment brought early value and strengthened the business case for a new, more efficient mode of brake testing. With the theory validated, the team then moved from proof of concept code to a production-ready app, now called Decelerator, in six short weeks.

The interface for Decelerator is about more than just good looks.

The streamlined interface directs users efficiently through the app’s different stages: from setup to completing a brake test and sharing the results. Subtle, bespoke animations and interactions bring Decelerator to life, helping users to understand when to provide input, and how to interpret test results.

The design of Decelerator required the team to build a deep understanding of the conditions in which the app would be used — something that would have been impossible without close collaboration with TfL staff, and in-situ user testing. This process revealed a wealth of invaluable insight that shaped the design of the app.

An early iteration of the interface, for example, incorporated a bright visual theme. This was popular with users but, when tested underground, created too much glare. This potentially hazardous problem was resolved quickly, thanks to the app’s centrally defined visual styles. A darker, less distracting visual theme was adopted in a matter of minutes, ready for immediate testing.

Continuing TfL’s long history of global firsts and pioneering innovation, Decelerator is the first app of its kind anywhere in the world. In 2017, it was piloted across three underground lines. For Year One, we aimed to reduce the number of trains removed from service by a minimum of 75%. This represented anticipated savings of £300,000 on these three lines alone, not to mention a dramatic reduction in lost customer hours, a key metric for TfL.

This is just the start of the potential savings Decelerator stands to make. Rolled out across the entire Underground network, and extended to other areas of transport, Decelerator has the capacity to save millions of pounds per year for TfL.