I do wonder though when we will have a 2nd generation of tilting train as back in 2000 the tilting train seemed a big modern futuristic thing that we would all travel on one day but since then only two types have been built (Class 221 and Class 390) and around 1/4 of the trains built have had their tilt disabled. Also since 2004 I don't think there has been any new TASS equipment installed.
There seem to be 2 camps - those that think tilt is fantastic and essential, and those that don't want it anywhere near their railway.
NR/SRA/DfT have passed up several opportunities to deploy tilting trains (eg TP routes, MML, Devon banks), and opted for non-tilt solutions instead.
There appears to be no likelihood of expanding the tilt route system.
Even the WCML system may have a short life left, with the arrival of HS2.
"Classic compatible" trains are unlikely to tilt, so that the minutes gained on HS2 will be dissipated further north by running at 110mph instead of 125.
WCML South may find it has to reduce to 110mph to maximise the frequency of new regional/local trains after the long-distance services are diverted to HS2.
The recent HS2 studies into northern high-speed routes seems to be bending towards new (straight) replacement lengths of the WCML.
The TASS/tilt system seems to have been a very successful technology and it is a pity it has not been exploited more.
I'm fairly sure it didn't have much to do with the cost overruns on the WCRM programme.
The track and OHLE would have to have been renewed and realigned anyway.
What is daft is Voyagers running around on XC routes with tilt disabled, while TPE run non-tilt trains on routes equipped with TASS.
The TPE order for class 185s (and then 350s) was a key point in the "rejection" of tilt.
Interestingly, tilt on the continent is primarily used to raise line speeds at quite a modest level (eg running at 160kph rather than 120kph), rather than for high-speed 200kph services as on the WCML.
Finally, the next round of bids for the ICWC franchise next year will determine the future of tilt in the UK.
If TPE's new order for 12 WCML trains includes 125mph tilt it would put some more momentum into the technology, and so would a plan to implement VT's desire to run at higher speeds than 125mph, to exploit the capability of the 390s.