The trains seem to be good at just picking up delay as they go, especially in the peak.
For example today 2C98 (14:12 York to Leeds) picked up 2 minutes of delay between York and Poppleton (seems to be common), 3 by Knaresborough, 4 at Starbeck, 5 at Harrogate, 6 at Hornbeam Park and Pannal, 7 at Weeton and Horsforth, 9 at Headingley, 10 at Burkey park and 11 minutes at Leeds
There just seems to be a recurring inability to stick to time even without taking the single line into account. I can’t really tell the differences between these trains and ones that stick rigorously to schedule (I’ve been on both)