Wisconsin & Southern Railroad engineer Matt Diestler cleaning the windows of his diesel locomotive, SD40-2 no. 4001, near Stoughton, Wisconsin. Diestler's mile-long train, the MAJ between Madison and Janesville, was stopped at the County Road B crossing to recharge the air in its brake line. Trains use a continuous air brake system with a normal operating pressure of 90 psi. Recharging after a stop can take several minutes on a train of this length.