Do any of the timetables elsewhere on EMR require the better running times of 170s? I imagine in Lincolnshire there isn't much running faster than 75mph but elsewhere there may be timings that require a 100mph unit.
It is an interesting question, but I don't think so.
From what I have seen the first routes to go over should be.
Worksop - Nottingham (I assume for 3 car running but from what people are saying on various threads they are not keeping up time, something that I don't recall as a problem under CT)
Leicester - Grimsby. The only place they can get about 75mph on this route is South / West of Nottingham, however considering the stopping pattern I think that is unlike.
I have not notice any difference in times between when the service is operated by a 156 over a 170.
Again I am sure train crew will correct me, but the only large routes with lots of 90mph running is Norwich - Liverpool which currently is planned to stay with 158s and the other regional routes getting the 170s.
I have used the joint line a few times (although on 156s) since the timetable change, it is noticeably quicker, but still at 75mph.
It is interesting that a lot of the regional services are "Pathed as Class 158/168/170/175" - So I don't know if their acceleration is better then the 156, but even back in CT days when local services could present 156, 158, 170 you could tell the difference end to end. The 153s were slower but that was because dwell times increase because of the overcrowding associated with them.