CTA President Forrest Claypool said most are at a Goose Island warehouse.
Among the items stored in the 333,000-square-foot facility are parts ordered for trains and buses that went out of service and items that were ordered in excessive quantities.
Claypool announced a cost-saving plan that includes the implementation of an electronic bar-coding system to better track items.
"Today, we are announcing that the CTA has begun a process to professionally manage its supply chain," said Claypool. "Effective immediately, all large and non-routine orders for parts and supplies will be reviewed by a central team to verify their purpose and quantities."
Claypool says any money the agency receives from selling off any salvageable items will go toward improving train stations and to buy new buses.