PROBLEM #$4$

A railroad bridge located at Sta$\mathrm{.}81+25$ is restricting sight distance on a $200-ft$ sag vertical

curve as shown in the figure below.

$($a$)$ Determine the grade of the forward tangent, $G_2$ in percent.

$($b$)$ Assuming that $G_2=+4$ percent, what should the speed limit be to ensure that stopping

sight distance is adequate on this curve?

$($c$)$ Although truck driver height was used in the equation in part $($b$),$ certainly the

clearance is not enough. If a clearance, $C,$ of $17$ feet is desired, if the $200-ft$ curve is to

be elongated what should the new length of the reconstructed curve be assuming that

BVC station does not change? Please note that an unequal tangent curve will result.