After "working" for some days creating the track route for the Kentucky Div. of the L&N, it occurred to me that especially folks new to this hobby of ours might want to know how to do it with at least reasonably accurate precision. So this "class" will ass/u/me that you have created a route and generated terrain, so now-----. First ASS/U/ME was a little reminder, kept on every officers desk at Southern Railway, that ASSUME makes an ASS of YOU and ME so. The most basic tools you will need are an earth view to digitize the route from, and information about the route, i.e. track charts. If your route is a fictitious one, then you do your own thing and those tools are optional. I prefer to simulate the real thing, either what is or what was. You will find, attached to this a page from the L&N track chart of the area of Richmond, KY.
I use Google Earth, so one of the first things is to digitize by placing points on the earth view to follow, as closely as possible, the center line of the main track. If it is double track then go to one end or the other and determine the main track as being the one that follows a straight path through the end turnout. OR, if the end turnout is a equilaters, that is one that deviates both ways, then I just the center between the two double tracks. It is tedious, but be as careful as you can and start a new digitizing path ever 20 miles or so, and when you finish a segment go back and inspect it and if point is far off the centerline, you can carefully select just that point and move it A TINY AMOUNT. Save the digitized line as a .kml file in a folder of your choice. There is a little program in the library, written many years ago, that converts .kml files to .mkr (marker) files. You will need that to create your marker file which only needs one line of gibberish at the top to make it digestable to TSRE. You can then cut & past other segments to the first one, and you can manually edit in specific points. Like FLS means a road crossing with flashers, FLSG is the same with gates, and FLGC is flashers, gates, and cantiliver. ABT is a bridge abutment. These are my names for special points, you call them what you wish.
The next step is to use the track chart to determine the distance between mileposts because HORRORS, they are rarely 5280 feet, and using the pushpins in Google Earth, mark the mileposts. Here is where some basic surveying practises enter the picture. Note the segment between mileposts 118 & 119 (circled number near top of page). What are these double arrows we see? Well these are "Equalties" and they are breaks in the original survey, usually because of line changes where the original survey was shortened (usually) or lengthened (occasionally). The left most one says it is station 6244.59.9 forward and station 6244+61.5 back and mile 118 is station 6227+27.1 (Note that the value of mile 119 shown as 5280+08 is an error, it should be 6280+08). Referring to the left break point, if we want the distance between mile 118 and the break, then we would do this subtraction: 6244+61.6 - 6227+27.1 which is the same as 6244.616-6227.271 or 17.345 but---. Stations are 100 feet apart, so this value is really 1,734.5 feet. From mile 117 to 118 is 5268 feet and since our printers do not produce nicely scaled prints, we need to measure the physical distance on paper, which in my case is 2-7/32, so 5268/2.218=2375.1 ft./inch. We also need to do the same for the vertical data. Those lines are 50 feet apart but I use the extreme distance of 100 feet, and the distance on paper is 1-1/16 inch. So 100/1.0625 = 94.1 ft./inch vertical. The vertical data should be the same for the whole page but the linear data may vary.
Now the gradient on the track chart may vary all over the place but this is because the values shown on the chart are compensated gradient values, i.e. allowing for the increased friction on curves which make the engine have to work harder because there is an effect of more grade. We don't have this yet in ORTS, so we want to know the true grade between obvious points like mileposts. If there is a large change then we might have to measure linearly to get the distance to the nearest mileposts and compute two gradients. Mile 118 to 117 is fairly smooth, so carefully measure the elevation of mile 118 & 117. Mile 118 is 5/32 inch above 900 feet so using the value in the previous paragraph, this is 5/32x94.1 or 14.7 ft. above 900, i.e. 914.7 feet. Likewise 117 is 3/32 above 850 feet. This i s 3/32x94.1 or 8.82 feet above 850, i.e. 858.8 feet. (I round up or down the hundreths). Now the expected gradient then is (914.7-858.8)/5268 = .0106 . Multiply by 100 to get the percent of grade - 1.06. By subtracting the station of mile 117 from that of mile 118 we got 52.68 (I ignored the .1 in the 118 station) and again 52.68x100 = 5268.
Okay, fine and dandy, but TSRE works on a metric system so we need to convert elevations to meters so that as we lay the track we will not exceed above or below the value for a check point more than a value we are comfortable with - I shoot for .5 meter. So burn this into your brain cells, you will need it a lot. 1 meter = 3.28 feet. so mile 118 for example is at 914.7 feet or 278.9 meters.
Track charts will vary as each railroad had their own way of designating things but looking at the example, you see 3 road crossings between 118 & 119 that have a cute little mark that looks like a flasher & gate, well that's what they have, flashers and gates. There are many turnouts with a short verticle mark at the points. This designates a manual turnout but it does tell us the size. #10 would be typical & I use that. Then at Ft. Estill North there is a turnout with a blacked in triangle at the points. This designates a powered turnout but again, so size is given. It could be any size but L&N standard would be a #15 so I will use that. Southern would be a #20. Signals are also shown but locations probably have changed for the intermediate ones like those between 117 & 118, so a close look at Google Earth is a must.
Now to lay track. I always place a track and a road piece in some obscure location underground, but not deep underground. In MSTS if you accidentally or on purpose deleted the frist piece that had been place of either track or road, then MSTS would crash, so I do this to avoid that problem which may or may not exist in TSRE. I will then place the first piece of "real track" and use the translate function to rotate it to as exactly the initial heading as possible. Then I attach a short piece to the starting end so I can adjust the gradient of this first "real piece" unless it is level. Continue placing pieces at the computed gradient until you come to a curve. I use M-tracks so I will select either the piece indicated for the correct degree or curve or I will use the nearest radius of X-tracks or default tracks. Remember that 3.28 value. Okay, in surveying there is a constant of 5729.7 that is used to determine radius or degree of curve, when the radius is in feet. So a value of 1746.86 divided by the degree will give us the radius in meters. I usually just use 1746 as it is easier to remember and you don't often encounter curves with fractions of feet or meters for radius, especially in our hobby. So a 300 meter curve is a 5.8 degree curve, i.e. 5 degrees, .8x60=48 minutes. M-tracks has the most common sizes of curves up to 10 degrees. So I lay out the entire curve using 20 degree segments, and then I adjust the length of the tangent leading into the curve until the exit lines up with the digitized tangent after the curve. Often takes a few tries. Then, especially if the following tangent is long, I will use as many 500M straight pieces as it takes to get to the next curve, well if it is less than a couple of miles maybe. Once I am satisfied with the alignment, I will replalce the 20 degree pieces with 10 degree pieces or smaller in the curve. Then I will relay the following tangent with shorter pieces so as not to have long tangent (or curve) pieces crossing a tile boundary. Again, that was a absolute NO-NO in MSTS and I ass/u/me that it is in TSRE as well. Hope this helps.
In adjusting the amount of curve to create accurate alignment of the following tanget, there are some useful piece in X-tracks and M-tracks. If you are in double track in M-tracks, there is a helpful piece there as well but not so much in MSTS double track. In single track, you can use a A1t6000r0_5 piece which is a 1/2 degree. Or in M-tracks you have 3 7minute curve pieces, almost imperceptible curve, as follows:
.1 degree : M1t0007d0001 1/10 degree of curve
.5 degree : M1t0007d0005 1/2 degree of curve
1 degree : M1t0007d0010 1 degree of curve
And you have those same 3 pieces in M2T--- double track pieces.
Jerry Sullivan, P.E. (retired)(retired from SR & CSX and as a docent on the C&TSRR)
TCHART002.jpg
I use Google Earth, so one of the first things is to digitize by placing points on the earth view to follow, as closely as possible, the center line of the main track. If it is double track then go to one end or the other and determine the main track as being the one that follows a straight path through the end turnout. OR, if the end turnout is a equilaters, that is one that deviates both ways, then I just the center between the two double tracks. It is tedious, but be as careful as you can and start a new digitizing path ever 20 miles or so, and when you finish a segment go back and inspect it and if point is far off the centerline, you can carefully select just that point and move it A TINY AMOUNT. Save the digitized line as a .kml file in a folder of your choice. There is a little program in the library, written many years ago, that converts .kml files to .mkr (marker) files. You will need that to create your marker file which only needs one line of gibberish at the top to make it digestable to TSRE. You can then cut & past other segments to the first one, and you can manually edit in specific points. Like FLS means a road crossing with flashers, FLSG is the same with gates, and FLGC is flashers, gates, and cantiliver. ABT is a bridge abutment. These are my names for special points, you call them what you wish.
The next step is to use the track chart to determine the distance between mileposts because HORRORS, they are rarely 5280 feet, and using the pushpins in Google Earth, mark the mileposts. Here is where some basic surveying practises enter the picture. Note the segment between mileposts 118 & 119 (circled number near top of page). What are these double arrows we see? Well these are "Equalties" and they are breaks in the original survey, usually because of line changes where the original survey was shortened (usually) or lengthened (occasionally). The left most one says it is station 6244.59.9 forward and station 6244+61.5 back and mile 118 is station 6227+27.1 (Note that the value of mile 119 shown as 5280+08 is an error, it should be 6280+08). Referring to the left break point, if we want the distance between mile 118 and the break, then we would do this subtraction: 6244+61.6 - 6227+27.1 which is the same as 6244.616-6227.271 or 17.345 but---. Stations are 100 feet apart, so this value is really 1,734.5 feet. From mile 117 to 118 is 5268 feet and since our printers do not produce nicely scaled prints, we need to measure the physical distance on paper, which in my case is 2-7/32, so 5268/2.218=2375.1 ft./inch. We also need to do the same for the vertical data. Those lines are 50 feet apart but I use the extreme distance of 100 feet, and the distance on paper is 1-1/16 inch. So 100/1.0625 = 94.1 ft./inch vertical. The vertical data should be the same for the whole page but the linear data may vary.
Now the gradient on the track chart may vary all over the place but this is because the values shown on the chart are compensated gradient values, i.e. allowing for the increased friction on curves which make the engine have to work harder because there is an effect of more grade. We don't have this yet in ORTS, so we want to know the true grade between obvious points like mileposts. If there is a large change then we might have to measure linearly to get the distance to the nearest mileposts and compute two gradients. Mile 118 to 117 is fairly smooth, so carefully measure the elevation of mile 118 & 117. Mile 118 is 5/32 inch above 900 feet so using the value in the previous paragraph, this is 5/32x94.1 or 14.7 ft. above 900, i.e. 914.7 feet. Likewise 117 is 3/32 above 850 feet. This i s 3/32x94.1 or 8.82 feet above 850, i.e. 858.8 feet. (I round up or down the hundreths). Now the expected gradient then is (914.7-858.8)/5268 = .0106 . Multiply by 100 to get the percent of grade - 1.06. By subtracting the station of mile 117 from that of mile 118 we got 52.68 (I ignored the .1 in the 118 station) and again 52.68x100 = 5268.
Okay, fine and dandy, but TSRE works on a metric system so we need to convert elevations to meters so that as we lay the track we will not exceed above or below the value for a check point more than a value we are comfortable with - I shoot for .5 meter. So burn this into your brain cells, you will need it a lot. 1 meter = 3.28 feet. so mile 118 for example is at 914.7 feet or 278.9 meters.
Track charts will vary as each railroad had their own way of designating things but looking at the example, you see 3 road crossings between 118 & 119 that have a cute little mark that looks like a flasher & gate, well that's what they have, flashers and gates. There are many turnouts with a short verticle mark at the points. This designates a manual turnout but it does tell us the size. #10 would be typical & I use that. Then at Ft. Estill North there is a turnout with a blacked in triangle at the points. This designates a powered turnout but again, so size is given. It could be any size but L&N standard would be a #15 so I will use that. Southern would be a #20. Signals are also shown but locations probably have changed for the intermediate ones like those between 117 & 118, so a close look at Google Earth is a must.
Now to lay track. I always place a track and a road piece in some obscure location underground, but not deep underground. In MSTS if you accidentally or on purpose deleted the frist piece that had been place of either track or road, then MSTS would crash, so I do this to avoid that problem which may or may not exist in TSRE. I will then place the first piece of "real track" and use the translate function to rotate it to as exactly the initial heading as possible. Then I attach a short piece to the starting end so I can adjust the gradient of this first "real piece" unless it is level. Continue placing pieces at the computed gradient until you come to a curve. I use M-tracks so I will select either the piece indicated for the correct degree or curve or I will use the nearest radius of X-tracks or default tracks. Remember that 3.28 value. Okay, in surveying there is a constant of 5729.7 that is used to determine radius or degree of curve, when the radius is in feet. So a value of 1746.86 divided by the degree will give us the radius in meters. I usually just use 1746 as it is easier to remember and you don't often encounter curves with fractions of feet or meters for radius, especially in our hobby. So a 300 meter curve is a 5.8 degree curve, i.e. 5 degrees, .8x60=48 minutes. M-tracks has the most common sizes of curves up to 10 degrees. So I lay out the entire curve using 20 degree segments, and then I adjust the length of the tangent leading into the curve until the exit lines up with the digitized tangent after the curve. Often takes a few tries. Then, especially if the following tangent is long, I will use as many 500M straight pieces as it takes to get to the next curve, well if it is less than a couple of miles maybe. Once I am satisfied with the alignment, I will replalce the 20 degree pieces with 10 degree pieces or smaller in the curve. Then I will relay the following tangent with shorter pieces so as not to have long tangent (or curve) pieces crossing a tile boundary. Again, that was a absolute NO-NO in MSTS and I ass/u/me that it is in TSRE as well. Hope this helps.
In adjusting the amount of curve to create accurate alignment of the following tanget, there are some useful piece in X-tracks and M-tracks. If you are in double track in M-tracks, there is a helpful piece there as well but not so much in MSTS double track. In single track, you can use a A1t6000r0_5 piece which is a 1/2 degree. Or in M-tracks you have 3 7minute curve pieces, almost imperceptible curve, as follows:
.1 degree : M1t0007d0001 1/10 degree of curve
.5 degree : M1t0007d0005 1/2 degree of curve
1 degree : M1t0007d0010 1 degree of curve
And you have those same 3 pieces in M2T--- double track pieces.
Jerry Sullivan, P.E. (retired)(retired from SR & CSX and as a docent on the C&TSRR)
TCHART002.jpg