It takes an iron man to play with a toy iron horse.
QUOTE: OVERHEAD: a. The wire heights specified (equivalent to 21' for city/interurban and 23' for heavy RR type operation) will accommodate the widest practical range of car and locomotive types. A height other than that specified may be used to simulate a specific prototype or a limited class of equipment, but may limit interchange of equipment. b. Normal wire height may be lowered thru underpasses and other obstructions, with consideration for the clearances of equipment to be operated.