I believe the O scale Diesel Catalog has not yet been put on line. HO Diesel is on line. You want to check to be sure you are ordering the correct parts. My original post was from my O scale paper Diesel Catalog. Their On-line catalogs and order system are at the most, a couple of years in the making, and appear to be an on-go-ing project. IMO still probably the best bet is the very nice paper catalogs listed on their website. There are minimum price orders, $20, less than $20 there is a $5 surcharge, they do try to push the business to their dealer network, eg. PD Hobbies. There is also a considerable wait time (3 weeks).
Largest catalog is O/On3 Steam Locomotive, which is available on line. 349 pages of parts with diagrams/pictures of the parts and another 100 or so pages of a price list. IMO not a bad reference source. There is a note that it is not available in hard copy. Mike CT
