trains sway and lurch to such an extent that it is dangerous to hold a newspaper or book while standing and work is impossible even when seated. Using an iPhone is almost impossible as one's fingers hit the wrong keys as a result of the instability. A few weeks ago I was almost thrown to the floor despite being seated on one of the end of carriage benches, such was the violence of the journey. Capacity is constrained by stupid errors in the recent past so no third liner can be installed for fast through trains and to facilitate maintenance (until recently there was sufficient space for this in the track roadway above ground).