Surveying the Right Of Way on the Springville and Southern R.R.
When my wife and I bought our property, one of the features I looked for, was a spot to build the backyard railroad. This is somtimes not easy to visualize when buying property but I felt the piece of land we chose, had a good potential track path. It was a couple of years after moving in that I was able to start the initial planning for the ROW (right of way). I walked the "imaginary" ROW many times before the first ounce of dirt was moved. I used a surveyor's transit to figure out what kind of grades I had to work with and to approximate how much cutting and filling had to be done. Here is how I approached the surveying part of the construction of my railroad.
- Surveyor's Transit. This is like a tripod mounted gun scope that can be accurately leveled.
- Surveyor's Rule. This is an 8 foot wooden ruler with large markings used in conjuction with the transit.
- 300 Foot Tape Measure. Used to measure long distances such as curve radii and track path length.
- Bailing Wire. Used to make "standard" measuring aids.
- Marking Flags. Small pastic flags mounted on stiff wire. Used to mark various features and distances on the proposed ROW.
- Wood Stakes. Used to mark low areas that need to be filled in. Also used to mark centers of track curve radii.
- Homemade Rule Tripod. This was made to hold the surveyor's rule when working alone.
- After choosing the path that my railroad will follow, I selected a reference/origin point from which all of my vertical measurements could be checked. The proposed track site has a non movable object in it (a pond) so I used a spot along side it as the reference point. I was fortunate to be able to see both ends of my line from this center point. I put a metal post in the ground at this point and marked it with a flag.
- Using my transit, I determined that the lowest point of the line is 5 feet lower than my reference point and the highest point on the line is 3 feet higher than the reference point. Using my tape measure, I measured the distance from the reference point along the path of the track, to both the highest and lowest points. This gave me the approximate grades I will have. All of which will be below 1 1/2 feet of change in elevation per 100 feet of track, or, a 1 1/2% grade. A manageable grade for my railroad.
- Using a piece of bailing wire (solid steel wire that's about 1/16" in diameter) I made a "standard" rule of 200 inches. This is just a length of wire with loops at each end, 200 inches apart. This gave me an easy, round number to work with when I used the transit to determine the track path according to grade.
- Starting at the reference point and working toward the upper, higher end of the line, I looped one end of the wire around the reference point post. With the wire stretched out straight, I placed another flag through the loop and into the ground at other end of the wire, and inline with the intended track path. I took the loop off of the reference point and once again stretched the wire straight and inline with the intended track path and placed another flag through the loop and into the ground. This continued until I reached the highest point of the line. I now have 18 flags placed in the ground each 200 inches apart from one another and inline with the intended track path.
- I knew that my highest point is 200 feet from the reference point and 3 feet higher. Since 3 is 1 1/2% of 200, My grade toward the highest point is 1 1/2%. The track towards the summit follows a path through a wooded area and the removal of trees was not an option. I had to stick to a predefined track path. This required excavating a good amount of earth in order to remove the high and low areas found along the track path.
- I set up my transit (level in all directions) so that I could see the reference point and as much of the R.O.W. towards the summit as possible. I also set my transit on a high spot so that with the surveyors rule set on the ground right next to the reference point, the 7 foot mark on the rule was on the cross hairs of the transit. This gave me a round number to start with and it also gave me a foot to play with in the negative direction in case of a low spot. To achieve a 1 1/2% grade to the summit, the change in elevation from one flag to the next would be 3 inches.
- With the transit set on 7 feet, the next flag ideally should read 6 foot 9 inches. If not, I wrote on the flag with a felt tip pen how much the difference is.
- Example 1:) The measurement at the next flag is 6 foot 7 inches. This means the ground is 2 inches too high and so I write +2 on the flag. This means 2 inches of earth will have to be removed from the track path to achieve a 1 1/2% grade.
- Example 2) The measurement at the next flag was 7 foot 2 inches. This means the ground is 5 inches too low and so I write -5 on the flag. This means I have to add 5 inches of fill in this area to achieve a 1 1/2% grade.
- After all of the flags toward the summit are finished, I moved the flags to the side of the ROW and excavated or filled the amounts written on the flags. It was necessary to check my excavation progress with the transit as I worked my way to the summit.
- The path of the track towards the lowest point of the line was handled differently. With the difference in elevation of 5 feet and the distance traveled being 500 feet, the grade on this end of the line would only be 1%. The track path on the lower end of the line runs through an open field. The only restraint I had was that the track had to end up at a certain point. This was the abutment for the trestle (the lowest point) at this end. I had a pretty good idea as to where the track would run but once the transit was used to locate the ideal grade, the track path varied from where I thought it would run by as much as 20 feet in one area.
- Starting once again from my reference point, I set the transit so I was able to see the reference point and as much of the intended track path as possible. This time, I set the cross hairs on the 2 foot mark of the rule to start with. A low spot along the track path was picked to get this reading. The 200 inch wire was once again placed around the reference point stake and this time the surveyor's rule was placed in the other loop.
- I placed the surveyor's rule, with the wire pulled straight next to the second flag on the "intended" track path. The measurement in the transit should have read 2 feet 2 inches. If not, with the wire remaining straight, I moved the rule uphill or down hill until the measurement read 2 feet 2 inches. I then moved the flag to this point and placed the loop of the wire over the flag.
- I removed the wire from the reference point, or preceding flag, and place the end of the surveyor's rule in this loop and straightened the wire out in the intended direction of the track path. The next measurement should have been be 2 foot 4 inches. Once again, if not, I moved the rule up hill or down hill to achieve this measurement. I continued this until all of the flags are in place between the reference point and the lowest point of the line.
- With these flags in place, I could see the ideal track path according to grade. This was, however, not the best track path according to minimum radius and I wanted to get some straight sections of track. I went back over the flags and moved them into a more desirable path. This meant some of the flags had to be moved uphill and some down hill.
- As was done on the upper end of the line, flag by flag, I measured the difference from the ideal measurement and the actual measurement taken, and marked the difference on each flag. This gave me the amount of cut or fill required to get the 1% grade.
- On this end of the line the cuts and fills were not too great. At the high spots, a 2 foot diameter patch of earth was removed around the flag according to the + amount written on each flag. In the low spots, a wooden stake was driven into the ground to a height according to the - amount written on each flag. The earth was then piled up to the top of each stake to achieve the proper grade.
- Once all of the flags were in place and the rough grades were achieved by filling or cutting, a shorter wire of 100 inches was made to more accurately check the elevations between each flag.
- After filling in and cutting out the low and high areas ,I smoothed and tamped the ROW and rechecked for high and low spots. I brought these areas to level using the transit and leveled the ROW from side to side with a 2 or 4 foot bubble level. The ROW was then ready for track laying.