If you can get a fairly recent track chart of the real railroad you want to simulate, it will probably be accurate but it may not have the wealth of information that was used in the old hand drawn or early CAD years. Case in point: Paris, KY to Maysville, KY branch of the L&N, now a shortline. The track chart that was available (from the L&NHS group) at a modest price was originally done in 1942 by hand and while there are upgrades, there is no date of such. This line would make a dog's hind leg look straight in comparison, so at mile 128.6 (from Louisville) we come to what is shown to be a 2 degree curve. But when we attempt to use 2 degree Mtrack pieces we find that whatever this curve is, it is a lot sharper than 2 degrees. In my professional experience I have seen many curves that were made sharper by the action of trains, especially if the engines were of the SD, i.e. 6 wheel trucks, variety. It is seen more often on branches that probably don't get as much maintenance as main lines.
So if you have digitized the line, using Google Earth (or I suppose some similiar program), carefully, you can determine what the degree of curve should be. Use the measuring tool and strike a line from the track out toward the center of the curve and perpindicular to the track. Save the result and do it again from another point and save. Where the lines cross is near the center of the curve, so you can measure from that point to the curve in meters. In my case this comes out to be 553 meters. Now a two degree curve would be 1746/2 = 873 meters, so 1746/553 = 3.15 degrees, or 3 degrees, 9 minutes. In M-tracks we have 3 degree or 3 degree, 30 minute curves, so we will use a 3 degree, or if we want to be really precise we can use dynamic track but I prefer to use as little of that as I can.
Note when using Google Earth to digitize a route, frequently hit the "R" key which will keep your view as near perpindicular to the ground as possible, otherwise parallax errors creep in.
Jerry Sullivan
So if you have digitized the line, using Google Earth (or I suppose some similiar program), carefully, you can determine what the degree of curve should be. Use the measuring tool and strike a line from the track out toward the center of the curve and perpindicular to the track. Save the result and do it again from another point and save. Where the lines cross is near the center of the curve, so you can measure from that point to the curve in meters. In my case this comes out to be 553 meters. Now a two degree curve would be 1746/2 = 873 meters, so 1746/553 = 3.15 degrees, or 3 degrees, 9 minutes. In M-tracks we have 3 degree or 3 degree, 30 minute curves, so we will use a 3 degree, or if we want to be really precise we can use dynamic track but I prefer to use as little of that as I can.
Note when using Google Earth to digitize a route, frequently hit the "R" key which will keep your view as near perpindicular to the ground as possible, otherwise parallax errors creep in.
Jerry Sullivan
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