transition curve in Atlas software

I keep on going back and forth between pencil and paper and computer for design. Is there a secret as to how to make a 90 degree turn, with transition curves? I can make a 14 inch radius turn, and I can make a transtion curve. But combining them into a nice 90 degree curve? Maybe I should stick with the paper and pencil.

 

I agree Barry. I have tried every one of the compter track plan programs, and they all suck big time! Probably, I feel, for the same reason we use Flex track for a lot of the curves on our layouts (and straights, for that matter), because theres no such thing as an 'even curve', really. I feel you'll find that even the colonels layout, where he makes mention of 14" turns is in reality flex track close to 14" (well, maybe exactly 14", but with built in transitions). Pencil and paper works every time....its just tedious which makes us look for an easier way...accuracy will always force us back to 'flexible' track planning with pencil and paper.

What I do is draw the track with blue pen on green graph paper, scan it into Paint Shop Pro (7.20), then split it across the CYMK channels and the magenta channel almost completely removes the graph paper marks and leaves the track in stark, black relief. You can then use your magic wand to highlight the track, cut it off, and paste it straight into a new transparent background picture ready for your scenery. works a treat.

f course, then you look at it and change your mind and have to do it all again...... LOL

 

yes, I am back to the pencil and paper. How do you draw your transition curves? Somewhere in the past I read how to use a bendable ruler, but I don't remember where. I've seen diagrams of how to do it with a batten, that may work fine for the layout, but that won't work for my 3/4" to 1' drawing.

 

Here's one link.

http://starwon.com.au/~pknife/transit.htm

I have the NMRA Data sheets, both the book and the CD. It has a very good chapter on them.

 

I bought Cadrail a while back and quickly decided I didn't need a new hobby. Paper and pencil work fine for me, I do not bother trying to draw in the transitional curves, they really don't consume enough space to worry about. In fact, all I do is: for 90 degree curves, measure from end of tangent the appropriate distance for desired radius (I use 3/4" = 1', so for instance 30" radius = 1 7/8"), make a mark, measure same distance at a right angle, make another mark, freehand draw in a curved line to conect tangents. The purpose of the drawing, for me anyway, is just to see if the track arraingement I desire will fit.

Gary

 

Transition curves in the Atlas Software are not hard at all. You have to get all of the curved pieces (transitions included) to toal an ANGLE of whatever you need (in your case 90). I use flex track pieces to fill in the actual curve.

For your 14" radius 90 degree curve with transitions (using N scale) just;

click "Special", "Transition curve"

Enter Radius 14.00
Angle 15.0
Curve 30.0
click "Left"
click "Ok"
paste this on the lower portion of the track plan area

Now do that again, but make a "Right" piece
and paste that in the upper portion of the track plan

Now make a flex track piece by;

click "Special", "Shape flex track"

click "Curve left"

Enter Radius 14.00
angle 15.0

click "Ok'

paste this somewhere in the middle

Clone this piece (Click "Duplicate existing element", then click on the piece of flex track)

Attach four pieces to the bottom "transition curve" (Click "Add track and connect" then add four pieces)

Click "Connect track" and connect the unattached transition curve to the last piece of flex you laid

PRESTO a 90 degree 14" radius turn with pretty long transition curves. You can play with the ANGLE settings of both the transition curves and flex track. A lower angle means a shorter piece of track.

Any ? please don't hesitate. I can email ya a .ral file if you would like.

HTH, Jim

[ 01. August 2002, 02:31: Message edited by: Jim Smith ]

 

A month ago I purchased the full version of 3rd Planit, a CAD program for model railroads. It has been great. Particularly for benchwork and transition curves. The other thing that has helped is drawing the benchwork with chalk on the floor to get an idea of the aisle width and access.

 

Plain and simpler the easyest way is to now bother with easments on the plan at all. They take up so little space it's not really worth it. Unless you're planning to print out your design 1:1 and use it as a guide to the building then it's just as easy to add the easments then. The track will drift slightly from the plan but in all likely hood when you come to doing the benchwork it's going to drift anyway. If it really bothers you add an extra ½" - 1" to your curve raidius in the plan to ensure there will be space.

 

Armstrong's Track Planning for Realistic Operation has a good explanation of the "bent stick" method for laying out transitions. I highly recommend this book.

As far as design software, the Atlas program is woth what you pay for it, i.e. nothing, IMHO. I picked up a $20-30 generic CAD program at Menard's that does everything I need for track planning, plus structure design, etc. I'll never go back to pencil and paper except for initial doodling.

One of the previous authors stated transitions don't need to be allowed for on the plan because they take up so little room. This is only partially true. Granted using transitions will cause tangents to be set out a fairly small amount, which you might not need to allow for on your plan.

But the first few inches of the tangent leading from the curve on your plan will not be straight when you add in the transition. Again, not a problem, unless your plan calls for a turnout to be located there. I got caught on this a little bit ago and had to forego the transition I had intended on using.

This still doesn't mean that you have to actually draw the transitions in on your plan, just that you need to be aware that the last few inches of straight track leading to a curve on your plan isn't really straight.

 

Don't foget you need at least 9 (more like 12) inches of 'straight' track to fit the transistion into. Depending on how much space you have -you might end up without room for transistion. With pencil and paper it is easy to cheat a little bit - the most common errors I see are tangents that are not tangent to a curve - even if you leave room for a transistion, if you goof up the tangent you will never get the curve to fit without sub-standard radius.

CAD does not let you cheat - but there is a learning curve - and yes it can be a 'new hobby' - particularly if you don't have much experince with CAD.

BTW - I've seen some great layouts that were NEVER planned on paper, CAD or anything else - building benchwork and started laying track works too.