Why is this while loop only doing the first loop? - python-3.x

Question

I am trying to produce some mechanical stress info from windspeed data for a crane boom when it is between 0 and 90 degrees, with data from each angle saved into it's own file. I have the script working fine when doing just one file/angle, however when I try and use any sort of loop to do it for all angles it will create the files, but only the first has any data in it. I am a beginner and am not very savvy with Python, so I was hoping someone could spot something simple I have missed. I have included a short example file of the source data: Windspeed source file - cut down
import math
file = open("C:/Users/Jacob/Desktop/BOM Data/HD01D_Data_074272_999999999523840.txt", 'r')
boomDirection = 0
vaneSpeed = 120
maxShear = 75.97043478
maxVonMises = 500.0216811
while boomDirection < 91:
data_file = open("Bolt Stress - " + str(boomDirection) + " Degrees.csv", 'w')
line = file.readline()
line = file.readline()
while line != '':
try:
if len(line.split(','))>1:
windSpeedHigh = int(line.split(',')[19])
windSpeedLow = int(line.split(',')[22])
windDirection = int(line.split(',')[14])
relSpeedHigh = math.sin(math.radians((90-(boomDirection - windDirection))))*windSpeedHigh
relSpeedLow = math.sin(math.radians((90-(boomDirection - windDirection))))*windSpeedLow
VonMisesHigh = (maxVonMises/vaneSpeed)* relSpeedHigh
VonMisesLow = (maxVonMises/vaneSpeed)* relSpeedLow
data_file.write(str(round(VonMisesHigh,1)) + ('\n'))
data_file.write(str(round(VonMisesLow,1)) + ('\n'))
except ValueError:
pass
line = file.readline()
data_file.close()
boomDirection = boomDirection + 1