Easement Curves

[Trainguy76]

Well, I've been using RW and RS for a long time now, and the only thing that I don't know enough about is easement curves. I assume others do too, so I wanted this topic to be a "general help with easement curves" type. So notes and questions are allowed, I'll start off.

Does anyone know how to change the pre-defined curve radius, it appears to be linked to the track-rule used.

[Trainguy76]

Apparently, the shorter track piece you lay, the wider the next predicted turn will be when easements is on. I think this is key.

[paulz6]

There is a very light grey (difficult to see) constant radius curve that shoots off at the end of the easement before it is laid.

[bdy26]

I've always found the easement tool very tricky. If you are following decals accurately you should end up with an easement anyway. Using the radius figure at the bottom whilst laying track normally can also be used to get a similar effect.

B

[paulz6]

I've always shied away from the easement tool in the past.
I can understand why it is required with super-elevation. There is a need to ease in the banking as much as easing in the curve.
I just hope we are not hampered by some silly colouring which is hard to follow on default terrain, yet alone over a decal.

[Kariban]

If only the track tool had a bezier curve option...

[Kromaatikse]

First of all, manually choosing different-radius curves to "simulate" a transition curve will not be sufficient to give you a true curve - without which you don't have a hope of superelevation. So if you've been doing that, You're Doing It Wrong. Sorry.

It's the same thing with gradient changes - you can break it up to make it less harsh (and a few routes like Portsmouth do this), but RW3 will make it truly smooth for you.

Secondly, I suspect that laying transition curves should be reasonably easy as long as you plan ahead and practice. If you see a curve up ahead, explore the transition space to see how far you need to lay straight track to meet the curve. Guidelines are laid out in front of you showing the limits of the transition already.

[FoggyMorning]

It's all very well saying we've been doing it wrong, but until last week nobody even had an inkling that ("proper") easements were going to be necessary superelevation to be used

[Kariban]

I had a go with this earlier, trying to lay a high-speed loop. The grey thing is almost impossible to see, and how are you meant to join sections using it? if you mess up surely you're not meant to pull up everything behind you.

I was also under the impression it created transition curves for you, but running into one at 240ish mph gave an almighty lurch.

[Trainguy76]

http://www.youtube.com/watch?v=v1BDFXjfZ2M

[paulz6]

What I am worried about is (RW3 hat on):
1.) Can we control the amount of easement easily?
2.) Can we control the amount of super-elevation on a curve?
3.) What happens about curved, or eased, pointwork?

I hope I do not need to constantly recompile track rules to get the desired effect.

[Trainguy76]

1.) Can we control the amount of easement easily?
2.) Can we control the amount of super-elevation on a curve?

I think both will be controlled in the track-rules, if I've read Derek's posts correctly.

I hope I do not need to constantly recompile track rules to get the desired effect.

Simple, use multiple track rules with the same spacing.

[moranb]

Using multiple track rules is normally not recommended (except for yards). A problem I have encountered with multiple track rules is changing the speed limits afterwards. It is very difficult to find where a piece of track laid with one track rules changes to another piece of track laid with a second track rule. In the end I had to change every reference to a track rule in the track.bin file to a single track rule in order to be able to adjust speed limits for different parts of a route.

BFM

[Kromaatikse]

One good technique might be to have a track rule for each common speed limit. That way, instead of setting the speed limits in post, you take them into account while building. This also makes sense because the length of each transition curve and the amount of superelevation each depend on the speed limit in force.

This does mean you need to do more homework before you start laying track, but you should get a better result afterwards.

Of course, I'm saying that as someone who has never written a track rule or completed a route...

[bdy26]

I guess we will need to see more from RSC as to how the superelevation will be implemented - i've not seen it said anywhere that the property of being easement laid is the trigger for the super elevation effect, but it is highly desireable for a smooth transition as sharp adjustments in track will be desperately noticeable with this effect on.

My understanding is that we will need to alter the track rule or tracks bin file to implement this on exisiting routes, but I would love to know more.

The easement tool is technically and theoretcially the best way of doing things, but it is extremely difficult to use in practice when following an actual route on decals on DEM terrain. Accuracy of route and gradient is incredibly important to get the track to site correctly in the terrain. When its done properly its amazing how it looks like the real thing, done slightly out it messes up miles of recreated route. Some of my route is laid by easements, but frankly I don't think it looks as good or rides as well (ineveitably you have to come out of that mode at some point) - I redid a section of the WCML last night, and it turned out far better without the easement tool - I tried both ways.

Not particularly easy in training, very difficult in a real routebuilding situation. User friendly it is not, but I don't think it actually matters that much IMHO.

Hopefully more info from RSC on this soon.

B