Oh, sorry, that I did not get notice of your entry for so long. But finally you get an answer, and hey, this is still faster than some answers from UG There are two options to get a system for what we want to do: 1) Define the direction by the marker. 2) Define the direction by the connected tool. I could have decided to take the way 2) but I decided for 1), And - there will always be a necessity for defining a direction because on a route there may be some showing segments in one and some in the other direction. So internally we must always deal with that. And what's against defining a direction by the markers? Ok, you must click once or twice for the start - and once or twice for the and, but is this so annoying? Another possibility would be to set the beginning and end node and then set the direction with a check button. But would that really be simpler and faster? Or - if you had only one drection you must decide if you want an incline or a descent. Or masts on the left or on the right side. It's a hypothetical question if that would be better - something like "coffee or tea".

There's something else: Think about circles. I admit it's a rare situation, but how would you define your route in a circle without defining a direction?

With my fences, the user builds two rail assets (start and end edge markers) on his side of choice. The side of the first asset is ignored, the second decides. As soon as the second asset is plopped, the fence is built and the markers bulldozed.
Fences are not critical and you may want finer control with your constructions, so you might need some more clicking (I am not sure). I imagine something like my fences, except the user must click either marker and gets a popup with: confirm, reverse, bulldoze markers. On confirm, the construction is built and the markers bulldozed; on reverse, the markers are bulldozed and rebuilt on the opposite side; on bulldoze, the markers are bulldozed. You might want to draw some arrow together with your markers, to make the direction more intuitive. Just an idea...

What fences do you mean? I only know Snowball's "legendary" fences mod, but did you create another? Please let me know. I would like to look at it and then we could discuss about your solution.

It's part of the freestyle station, you can find it in the waypoints menu.

Ok, after finishing another rather complex mod, I've looked at your fences in Freestyle Station. You use a marking method which is different from the one I use. Marking by waypoints is a cool idea. So you have no problems to define the direction because you can use the same mouse button for start and end and can define the direction by dragging the mouse pointer to one or the other side of the track. Ok, you have chosen this way, I have chosen another way which may be not so good. But at this moment I don't want to spend my time for improving a thing which at least is working because my To-do-list for other things is so long ... Maybe one day I'll experiment with your system, but you will have to wait. But - everybody could offer an improved alternative for my markers - this could be the advantage of my modular system you criticized so often. If you wanted you could create such an alternative based on your markers; you ony had to know the interface properties. This may be no problem. It's open to everyone.
But there could also be disadvantages. It's impossible to set waypoints at the ends of segments - ony about one meter behind. I don't know if it's possible to use my remote control funktion I implemented for shiftig a marker if it's out of range. There had to be a kind of proposal for setting waypoints. Another thing is that you had to use different marking tools for streets and tracks (at least I thinks so). I think both systems have advantages and disadvantages. And - by the way - the best would be if UG created an API feature for marking edges - something similar to the line marking or the zone marking but including directions.