Your article Turning the tide (NCE last week) indicates some, but far from all, the challenges on this project.
Track ability nder higher curving forces was the subject of investigation for both Pendolino and for the original tilting train, the Advanced Passenger Train (APT), the latter being initially charged with the objective of delivering 250kmh running on an unmodified west coast route.
The use of heavier track components was found to assist in track restraint, particularly in hot weather, and after maintenance when the track is most at risk from thermal forces.
However, this is not what I know as 'Absolute Track Geometry'. It is my understanding that ATG is the placing of track to a known design position and returning it to that exact position whenever it is maintained, rather than using relative position which leads to poor ride and ultimately faster deterioration.
It is ATG that has returned the west coast line to one of 'European' ride quality from its previous, legendary, poor quality. Such advances have been made possible by investment in new technology and sound engineering. I look forward to its more widespread use across Britain.
David M Johnson (F), chief executive officer, Laser Rail, Fitology House, Smedley Street East, Matlock, DE4 3GH