Chamber of Commerce was founded to aid area business growth and development. Conrail much later bought Pennsylvania Railroad, but the deal left out a stretch of track from North Vernon to Madison. Madison Port Authority purchased this, forming Madison Railroad in 1975. Madison's days as a leading Indiana city were numbered, however, when river traffic declined and new railroads built between Louisville, Indianapolis, and Cincinnati tapped into Madison's trade network. As a result, Madison's growth did not continue at the same pace it had experienced before the Civil War. During the late nineteenth century, many new buildings were still being built, but in many cases older structures were modernized by adding cast-iron storefronts and ornamental sheet metal cornices. Some earlier buildings survived without major alterations, and the Madison National Landmark Historic District today contains examples of all the major architectural styles of the nineteenth and early twentieth centuries, from Federal to Art Moderne. On January 11, 1992, Shanda Sharer was murdered in the city by four teenage girls. National Register of Historic Places Downtown Madison was granted National Historic Landmark District status in early 2006. On August 25, 2006, just months after the designation, a blaze severely damaged two historic downtown buildings, the Madison Elks Lodge and a former city hall building that was occupied by an insurance company. The Crawford-Whitehead-Ross House, Jefferson County Jail, Lanier Mansion, Madison Historic District, and Charles L. Shrewsbury House are listed on the National Register of Historic Places. Jefferson County Courthouse fire On May 20, 2009, the newly painted dome of the Jefferson County Courthouse caught fire. The blaze started around 6:15 pm. Smoke billowed hundreds of feet into the air and flames rose out of the clock tower. The fire continued to burn for hours. Fire officials reported that the fire was tentatively under control just before 9:45 pm. No major injuries were reported. The dome of the courthouse was being painted in celebration of Madison's bicentennial. On May 28, 2009, the ruined dome was removed from the top of the courthouse in two pieces. Authorities stated that the cause of the fire was a contractor using an open-flame propane torch to solder two pieces of copper together in one of the built-in gutters on the north side of the roof. Super Outbreak of tornadoes The 1974 Super Outbreak is the second-largest tornado outbreak on record for a single 24-hour period. From April