I'm going to lunch, let me know what you think....
Curve data doesn't check for one thing. Corner tie bearings also look suspicious.
I find the idea of spirals on the right of way so offensive that it's difficult to look at the curve.
But, when I do the curve length is about 4' short from what I calc. However, the stations work to the length I calc. And the curve length shown does not fit the chord distance of the curve I calc.
Lunch over, back to work.
Wow! Even your borrow pits are rectangular. Which section of the manual is that in?:)
Ok - During lunch I went down to the main office and pulled the as-built construction drawings to see if there where any mark up for the curve sthere wasn't any.
My siphering so far.
1st curve the data fits except L in the tabledoesn't match the stationing differences- stationing does match the curve infor for delta, Dc, and T. ok I can live with that.
the big curve is goofy- why have a spiral on a 30 minute curve- that should be simple- so I took I- total delta/ Dc and come up with 2920.0 which is L from the table plus 2 spiral lengths of 400 feet. OOOOOOOOkay......
the T length in the table is 2.75 feet different from calculated T using the Delta and Dc, and radius 11460.0- which 2 times that kinda explains the 6 equation....
FWIW the 3rd curve data checks, but the 4th doesn't.....:-|
Obedackuck 31:10 "Neatness is next to Godliness; therefore all of your angles shall be 90's. And there was much rejoicing"
My first job
with an engineering company (over 25 years ago) was in the road department. I was tasked with checking all the numbers on curves, etc. Before we had computers. I nearly wore out an HP41 but I don't believe a single set of plans went out with incorrect curve data. I understand the necessity of equalities (or equations as on these plans) but I never did like them. First place to look for errors in the field.
Andy
The Station 59+74.4 for the S.T. on the drawing is the Station for the C.S., not the S.T. Station. It appears that whomever did the calcs, subtracted the 400' instead of adding it to get the S.T. Station 63+74.4. The L for the simple curve is 2520.0'.
Check Out The Tangents
Each given tangent length includes a spiral?
Essentially the geometry is for a single radius curve. The spiral isn't a spiral, but a simple transition curve, exactly 1/2 the curvature of the main curve. All transition curves are 400'.
Some engineering department's idea of simplification. It is a simplification often used in laying out model railroad track.
Paul in PA
Actually!
What we are looking at is a typical set of Railroad plans from the early part of the 1900's! I'd would think the alignment was designed for trains traversing steep grades.
Railroad spiral calculations can be tedious and complicated!