92 Ill. Adm. Code 1535.606
Clearance Signs
Section 1535
Section 1535.606 Clearance
Signs
On all overhead railroad
structures having vertical clearance of less than 14'6" clearance, signs
are to be furnished, installed, maintained and replaced by and at the expense
of the public authority having the duty of maintaining the signs along the
highway requiring such signs or as covered by agreement. Said signs are to be
mounted on the sides of the overhead structure, one facing traffic approaching
from each direction, indicating in large legible figures the appropriate
numbers for clearance accommodated under the structure. It shall be the duty
of said public authority to determine the clearance to be indicated on said
sign. Railroad companies may elect to do the actual work of installing,
maintaining or replacing clearance signs. The railroad company shall notify as
soon as possible the public authority having such duties of any changes in
their grade separation structures affecting such clearances.