Now that the track is marked and I know how much to cut off, I measure that distance.
Then I flip the track over and use the ruler to mark cut lines on the bottom of the Kato track. I pick a spot BETWEEN the holes as you can see. The "ties" are over the holes so if I can cut in the middle all the time then you shouldn't be able to notice that the track has been cut.
The Kato track has the rail "fixed" on one end and movable on the other. If you look closely at the bottom of the rail to the right, you'll see 2 small dimples on the rail on both sides. This dimple locks the rail into the plastic roadbed / base such that the rail can't slide back and forth. The opposite end of the track piece does NOT have the dimples. This is important as when you cut the track, the piece of track that you want to slide off, has to slide off on the non-dimple side.
Here you see the two cut marks.
If not already done, the rail connectors, on both ends, need to be removed.