Hacky sim of acceleration over time, taking air resistance into effect until acceleration effectively becomes nil

Physics

#!/usr/bin/python
from time import sleep

mass = 303209.382 # Kg of a tube train roughly
force = 0.0 # Newtons, initially set to 0
accel = 0.0 # m/s^2, initially set to 0
power = 0.0 # Newtons, force being applied
drag = 0.0 # Newtons, air resistance
roll = 0.0 # Netwons, rolling resistance
velocity = 0.0 # m/s, speed

# start count at 0 seconds
count = 0
# set force to something
power = 16000.0

while True:
    force = power-drag-roll
    # f = m*a
    accel = force/mass
    # air resistance rule
    #       ???     air density      cube coefficient   cross-sectional area
    drag = 0.5 * 1.29 * (velocity * velocity) * 1.05 * 20.0
    # rolling resistance rule
    #    weight * gravity * rolling resistance coefficient of steel rail
    roll = mass * 9.81 * 0.001
    sleep(1)
    velocity += accel
    print('{0} s\t{1}N \t{2}m/s/s \t{3}m/s \t{4}KpH'.format(count, round(force, 2), round(accel, 2), round(velocity, 2), round((velocity * 60 * 60) / 1000, 2)))
    count += 1
    #if round(accel, 2) == 0.0:
    #    break