Columbia Railroad Bridge

The Columbia Railroad Bridge, which is also called the Columbia Bridge, is a bridge in the city of Philadelphia, Pennsylvania. It is run by the CSX Transportation train company, who uses the bridge to transport goods in the Trenton Subdivision area. The bridge goes over the Schuylkill River. It is in a park called Fairmont Park. 
First bridge.
The bridge has been built three times. First, it was built in 1834. It was a covered bridge. The bridge was made from pine tree wood. The government of the state of Pennsylvania and the Philadelphia and Columbia Railroad company built it. The bridge was bought by the Reading Railroad in 1851.
Second bridge.
The next bridge was built in 1886 by the Reading Railroad. It was made of iron and was very strong, so trains carrying very heavy things could go over it.
Third bridge.
Today's bridge was built in 1920.