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\fdO'^ - Old Forge Coal Mines

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274 RAILROAD LOCATION.<br />

of the parallel curve will be 819.02 - 100 = 719.02 ft. The<br />

chords on the 7° curve are each 100 ft., and we obtain the<br />

length of the parallel chords from the following proportion:<br />

819.02 : 719.02 :: 100 ft. : the required chord.<br />

Whence, we have required chord = —'.' —<br />

= 87. 79 ft.<br />

819.02<br />

(795) This question comes under Problem IV, Art.<br />

1426.<br />

^^17°10';ii;^=20M5'.<br />

2 2<br />

The distance between intersection points is 1,011 ft.<br />

From Art. 1426, we have<br />

(tan 17° 10' + tan 20° 45') : tan 17° 10' :: 1,011<br />

gent<br />

distance of the first curve.<br />

Whence, (.30891 + .37887) : .30891 :: 1,011<br />

gent distance.<br />

: the tan-<br />

ft. : the tan-<br />

Whence, tangent distance of the first curve = ..^'^^ =<br />

. Ob* I 8<br />

454.08 ft.<br />

Substituting known values in formula 91, T= R tan ^/<br />

(see Art. 1251), we have 454.08 = 7? X .30891; whence,<br />

R = ^oAon? = 1,469.94 ft. Dividing 5,730 ft.,<br />

. 30891<br />

the radius of<br />

a 1° curve, by 1,469.94, the length of the required radius,<br />

the quotient 3.899 is the degree of the required curve. Reducing<br />

the decimal to minutes, we have the degree of the<br />

required curves 3° 53.9'.<br />

(796) This question also comes under Problem IV,<br />

Art. 1426. We have<br />

2 2<br />

The distance between intersection points is 816 ft. From<br />

Art. 1426, we have<br />

(tan 10° 07' + tan 20° 34') : tan 10° 07' :: 816 ft. : the tangent<br />

distance of the first curve.

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