Whilst drivng this service. I got to just after cathcart heading for newton. I was doing 25mph. I dropped to 24mph so applied notch 1 back to 25mph and as you can see it shot up to 37mph and straight back down to 25mph just before the points as you can see. Never showed wheel slip action as i was hardly moving fast and weather was set to dry and summer. Just the speed went crazy for a split second. I did do a video but wont allow me to upload it to here. It came right out of no where. Never seen it before. Thought yous should know.
