Switch on Water-Trak, switch off Autumn chaos!
As autumn approached in 2022, we equipped a Northern Class 170 train with Water-Trak technology. The data we captured from 170473 provided us with a golden opportunity to explore autumn braking performance, comparing the train's capabilities with and without Water-Trak while operating over identical routes and in similar weather conditions.
The process began on October 31st when we started logging braking data. At 18:00 on November 2nd in Leeds station, the Water-Trak systems on 170473 were activated, and the results were nothing short of astonishing. We witnessed an immediate and sustained enhancement in average step 2 braking deceleration, increasing from 5%g to an impressive 5.9%g. To visualise this change, refer to Figure 1, a time series chart showing the braking deceleration over this period.
Figure 1: Time series chart of 170473 Step 2 deceleration before and after Water-Trak activation
Intrigued by these findings, we employed the Cusum method* to analyse the data. The outcome confirmed a statistically significant change aligning precisely with the activation of Water-Trak, as demonstrated in Figure 2.
Figure 2: Cusum chart of 170473 Step 2 deceleration
Naturally, a question arose: Could the rest of the Class 170 fleet be experiencing a similar transformation? To explore this possibility, we analysed the performance of the remaining Class 170 trains throughout autumn. Figure 3 illustrates the Cusum chart for fleet braking data, exhibiting a notable change point around October 10th. Braking deceleration dropped from 5.9%g to 5%g, marking the onset of autumn's challenging braking conditions. As we had hoped, no such change was detected on November 2nd, as the braking remained steady at 5%g.
Figure 3: Cusum chart of Class 170 fleet (excluding 170473) Step 2 deceleration
Figure 4 shows a time series chart for the 170 fleet (excluding 170473), highlighting the deceleration change on October 10th.
Figure 4: Time series chart of Class 170 Fleet (except 170473) Step 2 deceleration
The results obtained from train 170473 were remarkable, emphasising the substantial impact of Water-Trak on train braking. The technology significantly elevated braking performance, restoring it to levels observed before the onset of autumn braking conditions. It's crucial to note that these remarkable outcomes were achieved by the same train, operating on identical routes, and encountering nearly identical autumn weather conditions before and after Water-Trak's activation.
In conclusion, the evidence we've uncovered is undeniably compelling. Water-Trak has demonstrated greatly improved autumn braking performance offering the possibility of improved passenger safety and operational efficiency.
*The Cusum method is a statistical technique used for detecting changes or shifts in data patterns over time.
