I think I've encountered bug between my version of RailClone and yours.
I've made 2 gifs to demonstrate the problem:
1st gif I made in 3ds Max 2016 and 2nd was your file in 3ds Max 2017
On the first one (my object, created from scratch), when I resize the spline, the tiles are pushed to the right side, creating tiles that are cut and not perfect in size
On the second gif (your object), as I resize your spline, the tiles stay in the middle and thus resize perfectly.
When I use "Copy Style to" feature from your object to mine it works as it's supposed to.
So my question is - Is this a bug (I have the latest versions for both 2016 and 2017, but when I loaded your scene it said that your version might be newer) or is it some option I didn't apply?