E6007
Member
I believe there were issues at LM with clearing double sets of 350/1s for 110mph running with two pantographs. Unsure whether they are cleared to run at 110mph with three but I very much doubt it as no 12 car is booked to run on the fast lines via Weedon to my knowledge. So if 12 cars to Corby is essential then clearances may need to be made in order to allow a triple set 350 running at 110mph. Otherwise I am guessing it's be max 100mph with a triple set and max 110mph north of Kettering with a double set from the day of introduction.
It might have taken a while but 12 car 350's are cleared for 110mph and operate at that speed everyday, e.g. 17:13, 17:49 and 18:13 from Euston in the evening peak.