You can't whack older units straight into full power as it's likely to trip the overloads. Mechanical sympathy means drivers usually work through the notches in sequence, or start in 2 and then into 4 around 8-10mph which may be what you experience. The jolt is particularly noticeable on an uphill gradient as sometimes in notch 2 it feels like the train won't move at all!Has anyone else experienced a very jolty ride on a 455? I’ve been on a few where they leave the station at about 5mph until the driving carriage is off the platform they they jerk and start to accelerate. Not sure why the ride quality isn’t great