This particular vehicle No. 7 was virtually brand new when purchased. It was put in the charge of the senior driver, Horace Gutteridge, and he assumed sole priority in its use. Inevitably, a time soon arose when he was not available. An urgent order and immediate delivery was received for a load of bricks to be sent to Rhuddlan. This brand new wagon was the only one available at the brick-works and so it was 'borrowed' by the next most senior driver, Horace Williams. The driver was not familiar with the steam tipper gear and, after unloading the bricks at Rhuddlan, he inadvertantly left the valve open on commencing his return journey. By the time the Sentinel had reached St Asaph, steam pressure had built up and, besides propelling the vehicle, entered the tipping mechanism and began to elevate the platform as the vehicle was in motion.