I need some R.R. savvy surveyor's thoughts

You Are Assuming The Track Maintenance Crew Can Read Plans

At best those plans were used to build it 100+ years ago. Extra tracks come and go, ties come and go, why should it look like that now?

You have fences that agree with the geometry, stay off the right of way.

Paul in PA

Paden,

You are using the arc definition. Railroads are built on a chord definition curve.

John

I Don't Think Paden Drew Those Plans With Highway Curves

They are what they are.

Paul in PA

You Are Assuming The Track Maintenance Crew Can Read Plans

ditto

The new rail locations have been designed to keep the faster trains on the track.

All the rails I've ever tied in were a best fit situation unless I could actually locate some original features from those original plans, like some structure.

Have not seen an actual mile marker in years that were actually a mile apart.

The alignment of the ROW can depend upon when the spirals were placed. I notice there is spiral information below the curve data. I have staked new railroad ROW to include spirals in the ROW. The old school of thinking was that the original alignment generally did not have spirals, so the ROW conforms to that original alignment and not what exists today. If you do decide to determine the alignment with the spirals, I'd be glad to help with the geometry.

I agree JP. It is interesting that the equation station 26323+08.2(bk) is the same as the PS station in the spiral data you referenced. It appears that something has changed over the years.......

Nice plans, railroad right-of-ways are almost always based on simple curves. Of course there are exceptions, but they are rare. In this case you have a 3 degree curve. I would locate the tangents and see how they fit the geometry. It's remarkable how nice I've had them fit in the past (and don't forget that these are probably "true" north surveys). Then in the curve section the track will have spirals, even if they weren't staked or designed to have them the trains will create them.

The old railroad engineers seemed to understand what new engineers don't. Design the ROW with simple curves and the tracks with spiral-curve-spiral. So the tracks will not quite follow the right of way through the curve which is expected.

Newer valuation maps will show the curve with spirals which is correct for the tracks but incorrect if you are staking the ROW. For that you often need the older set of plans.

And you want to look for those railroad right of way monuments-rails driven into the ground. I see them once in a while.

Appears that there are a lot of mislabeling of the parameters, stationing running backwards (getting smaller)from what is labeled P.C. Calc'ing a 1°08' curve does not match the data given on the drawing, except for the radius.

All Data Is Correct For A Highway Curve

That is what my HP 48 w/SMI says.

A 1°08' curve with a 100.00' chord is 100.0016' on the curve. As far as significant digits go this railway curve is a highway curve.

Paul in PA

All Data Is Correct For A Highway Curve

I missed a number which made it appear that the stationing was getting smaller going from the labeled P.C. station. the only thing that doesn't check for a Hwy curve is the radius given. That checks a RR curve calculation.

> Is there any indication on this print that the rails would not follow the simple curve data shown?
>
>

you mean besides the big honkin' note center bottom that sez "track Alignment"?

> You are using the arc definition. Railroads are built on a chord definition curve.
And spirals. You have 970' spiral curves there.

All Data Is Correct For A Highway Curve

Paul:

The data for each of the curves is pretty similar for the highway curve and the railroad curve. Some data as tabulated on the drawing appears to be from using the chord definition, i.e. the radius and external.

Highway Curve Data

Delta : 60° 26' 00"
Radius : 5,055.510
Arc : 5,332.353
Chord : 5,088.586
Tangent : 2,944.346
Doc Arc : 1° 08' 00"
Doc Chd : 1° 08' 00"
MidOrd : 686.900
ExtOrd : 794.905
Sector : 13,478,870.54
Fillet : 1,406,287.00

Railroad Curve Data

Delta : 60° 26' 00"
Radius : 5,055.592
Arc : 5,332.438
Chord : 5,088.668
Tangent : 2,944.393
Doc Arc : 1° 07' 60"
Doc Chd : 1° 08' 00"
MidOrd : 686.911
ExtOrd : 794.918
Sector : 13,479,307.79
Fillet : 1,406,337.32

Norman:

The spirals pertain to the track layout, not the survey line.

All Data Is CLOSE TO a Highway Curve

At 1d 08' there isn't much difference, but the radius, length, and tangent numbers indicate that the curves were calculated by railroad formulas.

My eyes are old

I scoured these a little more with all y'alls help.

I was thrown by the spiral data which appeared to me to be on the old alignment stationing (it doesn't show very well in my pic). Apparently the new alignment carries two stationings.

Usually the RW location would be good enough for what we do. In this instance there will be utility poles inside the Ry. RW and there are clearances that have to be shown to the rails. I was just trying to compare the rail location (shot every 50') with the math.

In any event, the clearance will be shown to the existing rail, not the planned location. I was just trying to see how well the existing fit the planned.

Thanks for everyone's input, it only reinforces the way I signed my original post!

Correction, All Data Is Correct For A Railroad Curve

Kinda thinking too fast before.

One thing to remember, there is no arc measurement along the arc on the railroad. All curve measurements are along the 100' chords and the two short chords.

Therefore the length of the curve is 5332.35'. Just because a calculator says the arc is 5332.435' that arc does not exist in railroading.

Paul in PA

My eyes are old

The better question is, where are you obtaining these R.R. Plans?

BLH

Where?

At the gettin' place!;-)

Seriously, over the years I've kept a few names and phone numbers of folks. They are getting harder to come by 'cause some have retired. Available records are spotty. If you've got a specific need, let me know and I'll see if I can hook you up.