216
MOLESWORTH S POCKET-BOOK
Form c læ for Setting out Railway Curves
iri9C
R=
—*
•X
R=Radins of curve.
T=Length of tangent.
x=Half angle of intersec-
tion.
D=Distance of centre of curve
from intersection.
C=Any chord.
A=Tangential angle of C in
minutes.
R=T (tan. a>).
T=R (cotang. x).
D=R (cosecant x- 1).
, 1719C
A=— '
S=R (cosine x).
V=R (coversine x).
5400 — x
Number of chords in the curve =-;---•
A
Length of the curve = ’000582 R (5400 — ®).
Note.—x and A in the two preceding formula1 must be ex-
pressed in minutes.
Table op Tangential Angles for 1 Chain Chords.
Rad. of
Curve
Chains.
Tangl.
Angle.
Bad. of
Curve
Chains.
Tangl. Ec^;v°f
Anf?la- 'Chains.!
Tangl.
Angle.
Rad. I
of
Curve.
Tangl.
Angle.
10
12
5° 43-8
' 34*87
51-9
I 2 23*25
15
20
25
30
35
1 20*95
1 876
67-3
49*11
40
45
50
60
70
42'-97
88 -2
34 -38
28 ’65
24 -5Ö
1 mile
2 miles
21'-48
17 *19
14 *33
12 -28
10 -74
3
3
2
Note.—The angle for 2 chain chords is double the angle for 1 chain
chords. The angle for | chain chorda ia | the angle for 1 chain chords.
Curves of less than 20 chuins radius should be set out in f chain chorda.
Curves of more than 1 mile radius may be set out in 2 chain chorda.
The angles in the above Table are in degrees, minutes, and decimals of
miaute».