Hi Madalyn,
You want a path parallel to the railroad tracks, which means you want a path which has the same slope as the railroad tracks. To compute that slope:
m= (y2-y1)/(x2-x1)
x1=8
x2=11
y1=0
y2=4
m= (4-0)/(11-8)
m= 4/3
Now, we want a line that passes through the point (4, 5) with that slope. You didn't specify a form for the equation, so I'll use point-slope. Let me know if you need slope-intercept or general. Anyway, point-slope form is:
y-y1=m(x-x1)
x1=x-coordinate
y1=y-coordinate
m=slope
So:
x1=4
y1=5
m=4/3
Equation: y-5 = (4/3) (x-4)
I hope this helps.