The Bronx Zoo spent nearly 5 million dollars in the mid 2000’s to repair there monorail cars. The idea was to prolong there life for decades to come.
https://schwagerdavis.com/wp-content/uploads/2016/10/SDI_BronxZoo_ProjectReport.pdf
https://schwagerdavis.com/wp-content/uploads/2016/10/SDI_BronxZoo_ProjectReport.pdf