Railroad Frog

Intersecting railroad tracks cross through each other on a special track section called a railroad frog. Any clues how it became known as a frog other then a visual similiarly to a crushed, splayed and dried real frog?

Some explanation if curious:
www.romarpipeandrail.com/ turnouts__&_switch_components.htm

or

www.web.mit.edu/ Invent/www/InventorsR-Z/Westinghouse.html