INTRODUCTION

CHICAGO, AMERICA'S THIRD LARGEST CITY, SAW IT'S METEORIC RISE INTO WORLD HISTORY THROUGH THE 19TH CENTURY. BLESSED WITH TWO MAJOR GEOPHYSICAL FEATURES, THE VAST LAKE MICHIGAN AND THE CHICAGO RIVER, A TRIBUTARY OF THE MISSISSIPPI, IT BECAME THE COUNTRY'S TRANSPORTATION HUB BY MID-CENTURY. BUT IT WAS UNPRECEDENTED ENGINEERING FEATS, SHARP BUSINESS DEALS, AND A LITTLE HUBRIS THAT MADE CHICAGO A METROPOLIS.

LAKE MICHIGAN PROVIDED A WATERWAY TO THE EAST. IT ALSO MADE CHICAGO NATURALLY WATER-LOGGED. BUT BY SINKING IMMENSE CONCRETE FOUNDATIONS, CHICAGOANS WERE ABLE TO TRANSFORM A SWAMP INTO THE HOME OF THE WORLD'S FIRST SKYSCRAPERS--WILLIAM LEBARON JENNY'S HOME INSURANCE BUILDING OF 1885 PAVED THE WAY FOR GENERATIONS OF VERTICALLY-INCLINED ENGINEERING EXPERIMENTS.

THE RIVER CONNECTED THE LAKE TO THE MIDWEST AND WAS SUPPLEMENTED BY THE 96-MILE ILLINOIS & MICHIGAN CANAL OF 1848. BUT THE RIVER FLOWED INTO LAKE MICHIGAN, CREATING A PUBLIC-HEALTH DISASTER. IN 1900 THE SANITARY DISTRICT OF CHICAGO REVERSED THE RIVER'S FLOW, SENDING IT AWAY FROM THE LAKE AND INTO THE MISSISSIPPI, WHILE MOVING IT'S LOCATION FROM MONROE ST. SEVERAL BLOCKS NORTH TO ITS PRESENT LOCATION ALONG WACKER DR.

MEANWHILE, RAILROADS BEGAN TO SPREAD ACROSS AMERICA. CHICAGOANS WERE QUICK TO TAKE PART IN THE INDUSTRY, AND SUCH FAMOUS BUSINESSMEN AS WALTER NEWBERRY AND WILLIAM BUTLER OGDEN FORMED MAJOR NATIONAL RAILWAY COMPANIES. CHICAGO WAS SOON THE CENTER OF A TRANSCONTINENTAL SHIPPING SYSTEM, AS THE FIRST DIRECT ROUTE TO THE PACIFIC OPENED IN 1869.

WHERE THESE RAILWAYS MET THE RIVER PROVIDED ANOTHER CHALLENGE TO BE TRIUMPHANTLY MET WITH ENGINEERING INNOVATIONS. NEW MOVABLE BRIDGES LIFTED, PIVOTED, SWUNG, AND RETRACTED, ALLOWING BOATS AND RAILROADS TO CO-CONSPIRE IN THE INDUSTRIAL ECONOMY. THE TRUNNION BASCULE BRIDGE, A COMMON DRAWBRIDGE DESIGN THAT EMPLOYS HEAVY COUNTERWEIGHTS WHICH ROTATE AROUND A TRUNNION-AXLE, LIFTING THE SPAN, WAS A CHICAGO INVENTION THAT FIRST APPEARED IN 1902. AT ONE TIME MORE THAN 50 BRIDGES CROSSED CHICAGO'S RIVER-SYSTEM. SOMEWHERE CLOSE TO 46 ARE PRESENT TODAY, MANY OF THEM TESTAMENTS TO THE GLORY OF CHICAGO'S INNOVATIVE SOLUTIONS OF THE LATE 19TH AND EARLY 20TH CENTURIES.

TAKOTRON HERE PRESENTS SEVERAL NOTABLE EXAMPLES OF THESE MOVEABLE BRIDGES, FOUND, VISITED, PHOTOGRAPHED, AND ADMIRED. BECAUSE THESE BRIDGES RUN ALONG RAIL LINES, NOT PUBLIC STREETS, THEY ARE LISTED BY THOSE STREETS CLOSEST TO THEM.