Hi all,
I am trying to reconstruct a R/R right of way, but it is giving me fits! There are 3 curves that combine to make one nasty compound curve. I can't figure out if the stations are along a 100 ft chord or an arc and my delta is not coming out right. I was wondering if there are any experts on this that are willing to give me a hand.
Info:
Bearing In: S25 38 30W
PC - 3689+60
degree of curve = 2 00
PCC - 3694+00
degree of curve = 4 00
PCC - 3698+00
degree of curve = 2 00
PT - 3703+00
DELTA = 39 29 30
Bearing Out:S65 08W
Any help getting this into CADD would be greatly appreciated!
Use the equation R=50/sin0.5D and draw the curves in using the radius and degree of curve.
Possible Solution: Railroad R/W reconstruction
I suspect a degree of curve error.
Analyzing each curve results in:
For chord defined curves -
Length 1 = 369400 - 368960 = 440
Length 2 = 369800 - 369400 = 400
Length 3 = 370300 - 369800 = 500
deflection = D x Len/100
deflection 1 = 2 x 440/100 = 8.8 deg = 8 deg 48 min
deflection 2 = 4 x 400/100 = 16 deg
deflection 3 = 2 x 500/100 = 10 deg
total deflection = 34.8 deg = 34 deg 48 min
total deflection from directional difference
S65 08W - S25 38 30W = 39 29 30
This may suggest that the degree of curve may be incorrect
for the curve from 3689+60 to 3694+00. If the 10 and 16 deg
deflection is subtracted from the total, the result is:
39 29 30 - (10 + 16) = 13 29 30
D = degree of curve
D = deflection / (Len/100)
D = 13 29 30 / (440/100) = 3 deg 4 min
Other information might suggest a differing solution!
Possible Solution: Railroad R/W reconstruction
It used to be that most railroad curves were spiral curves not compound curves..that could be throwing you off
i have the cad solution i think, please let me know your email and i will send.
Check against the original RR maps and you should find the curve details you are looking for.
Most RRs were aligned amazingly close.
The hardest thing is to find something that will connect the stations of the plan to the alignment on the ground. Don't rule out anything along the tracks.
Things tend to move as the tracks are rebuilt and modernized. Still many things remain in the same place.
On the last RR I had to retrace, the only thing on the ground that checked with stations on the plans were the stations to a bridge.
> Hi all,
>
> I am trying to reconstruct a R/R right of way, but it is giving me fits! There are 3 curves that combine to make one nasty compound curve. I can't figure out if the stations are along a 100 ft chord or an arc and my delta is not coming out right. I was wondering if there are any experts on this that are willing to give me a hand.
>
> Info:
>
> Bearing In: S25 38 30W
> PC - 3689+60
> degree of curve = 2 00
> PCC - 3694+00
> degree of curve = 4 00
> PCC - 3698+00
> degree of curve = 2 00
> PT - 3703+00
>
> DELTA = 39 29 30
>
> Bearing Out:S65 08W
>
> Any help getting this into CADD would be greatly appreciated!
If you need a consultant on this contact:
Dwayne Gresham, the main principal started out surveying for the A.T. & S.F. RR.
He understands railroads.
great thank you!
cjones@generalsurveys.us
this has been abandoned for 30+ years. no track or anything is left.
so far I have found a stone drain called for, a r/w stone with X and 2 drain pipes under the old ballast.
also have station on the county road that crosses. Though if I don't get the curve in correctly, 1/2 the evidence I found is useless, as it is on the other side of the curves.
Railroads typically used the chord definition for curves and spirals in and out of circular curves, the notation you show, is for circular curve to circular curve. You should be able to intersect the tangents and locate the PI to work from, if all else fails.
jud
Do not waste time on the spirals. Though the centerline may well have them, the R/W will be circular. Sometimes the R/W curves are chord method, sometimes arc. Quality and quantity of data on RR maps varies greatly. A few ties to evidence on the ground will find what you need. Even a ground probe can be used to find the compacted ground under the track and ballast that was removed and aid in location reconstruction.
Just beware of followers. I have seen engineers who insist the R/W is spiral when no evidence could possible suggest such.
This is typical of the western states. You can find variations of all sorts on rare occasions.
Possible Solution: Railroad R/W reconstruction
Think this could be a spiral?
to be fair, the curve control is not labeled. So PCC is what I labeled it as, as I thought it was a compound.
Possible Solution: Railroad R/W reconstruction
"It used to be that most railroad curves were spiral curves not compound curves..that could be throwing you off"
Not on the ROW!!
