In 2005, the CTA embarked on a project to replace six deteriorating viaducts on the Evanston branch of the Purple Line. The poor condition of the century-old viaducts forced the implementation of permanent slow zones and were a point of contention for many Evanston politicians. They claimed CTA had secured funds and promised to begin replacing the viaducts starting in 1999, but had diverted the funds to other projects. The CTA responded that it only provided projected uses and had not committed the money to any specific purpose. The Main Street viaduct was completely replaced over the weekend of November 12–13, 2005, requiring the temporary shutdown of the Purple Line. Construction was completed by the Monday morning rush hour. The Church Street viaduct was replaced next; preliminary work at that location began in July 2006 and the new viaduct was installed in late October 2006 during another weekend closure of the Purple Line.