All tracks (except main, passing, ladder, or other open throughfare tracks) spanned by overhead platforms used for icing or other loading purposes, may have vertical clearances less than twenty-one (21) feet six (6) inches provided such platforms or structures are so constructed as to open upward or outward by means of counterweights or other devices and thus provide clearances required by Section 1500.170(b) and (c) at times when cars are being handled over the tracks served by such platforms.
Ill. Admin. Code tit. 92, § 1500.190