Find a catalog for Lionel model train parts at BrasseurElectricTrains.com. Search for specific Lionel parts by selecting "Lionel (O & O-27)," which links to an extensive library of Lionel train parts.
Other websites that sell Lionel train parts include LionelSupport.com and HobbySurplus.com. Lionelsupport.com is Lionel's support website. It sells replacement parts and has information on Lionel train repair and service work. HobbySurplus.com has a helpful Repair Parts Catalog that you can download to your computer for further searching offline, as well as a guide to ordering the correct repair parts for any Lionel train. Both sites have huge inventories of Lionel train parts.