Section 238.221 - Glazing(a) Passenger equipment shall comply with the applicable Safety Glazing Standards contained in part 223 of this chapter, if required by that part.(b) Each exterior window on a locomotive cab and a passenger car shall remain in place when subjected to:(1) The forces described in part 223 of this chapter; and(2) The forces due to air pressure differences caused when two trains pass at the minimum separation for two adjacent tracks, while traveling in opposite directions, each train traveling at the maximum authorized speed.