I'll attempt to list various bits of info on detail parts in general and also specifically for the Red Caboose gp9. This may take more than one attempt, as I remember or find useful information along the way.
For starters, I'll run down the detail parts listing at Des Plaines. As noted, the website is mostly useless for identifying parts, as there aren't any photos, and barely any descriptions.
In the O scale details category, the items are listed alphabetically by manufacturer. If you go to the part manufacturer's website, you can often find drawing or photo representation of the parts.
190-**** - Cal-Scale,
O scale parts page
585-**** - Precision Scale,
O scale parts catalog
AFT - Archer resin detail decals,
O scale page
DPO - unknown
DRL - unknown
GLP - Grandt Line Products, now owned by
San Juan Car Company
GPM -
Glacier Park Models
HTD -
High Tech Details, part of Glacier Park Models
KVM -
KV Models - etched metal parts
LWP -
Lines West Products - 3d printed Milwaukee Road prototypes
MRM -
Mullet River Models - now owned by Des Plaines
OSA -
O Scale America - Des Plaines house brand, a combination of ex-Custom Finishing parts and new run parts
SJC -
San Juan Car Company
TTG -
Tichy Train Group
I see that Des Plaines does have a few photos available with some of their OSA parts, but the vast majority still lack information. As noted above, a fair amount of the O Scale America is ex-Custom Finishing. Attached at the end of the post will be a pdf of an old Custom Finishing "catalog" that has drawings of the various parts. It's not the greatest, but it sure beats nothing at all. The Custom Finishing parts numbers listed in the catalog are the same as the OSA numbers listed on the DPH website, except the prefix has been changed to OSA.
Any OSA parts not found in the number range of the old Custom Finishing parts are things that DPH has developed themselves, or possibly acquired from another company. They have (or had, before Ron Sebastian passed away) made a habit of acquiring other lines when original owners pass or retire. The Custom Finishing numbers run from 900 to 1052, the new OSA parts run from 800 ish to 899 and from 1053 onwards.
Some notable examples of useful OSA parts for modifying the gp9 include:
OSA805 - Fan hatch to convert to 48" fans
OSA807 - Windshield for low nose versions
OSA1020 - Rooftop air tank ends for steam generator equipped locos
OSA1032 - EMD handrail stanchions - cast - not currently on the website, which usually means not in stock
OSA1057 - Etched metal step and louver detail sheet - not currently on the website, so not in stock
There are also several steam generator and headlight parts if needed for a specific prototype.
P&D Hobby also has an extensive collection of detail parts. P&D and Des Plaines will be the two logical places to look for detailing items for the gp9 and many other locos. P&D has done a better job in recent years of adding photos to their website, although they still aren't the greatest for seeing the parts. Again, better than nothing.
There is a lot of overlap in parts between the two vendors. Both in terms of manufacturers and in terms of parts. P&D has a house brand of parts, like DPH some parts are newly developed and some are acquired (old Kemtron brass for example). Interestingly, P&D also stocks a fair amount of OSA parts. So in a twist, you can go to the P&D website and see photos of OSA parts, which you can't see on the DPH website. The OSA parts will be listed at P&D as Custom Finishing, or CUF, rather than OSA. Like DPH, P&D also carries Hi-Tech and Cal-Scale. Unlike DPH, P&D has a large assortment of Precision Scale parts.
One thing that is interesting for both vendors, they both had the primary owners pass away in the past year or two. Both stores have continued on with family taking over the day to day operations. However, both Pat Mucci at P&D and Ron Sebastian at Des Plaines were the driving factors in their respective store's involvement in O scale trains, and I'm not sure how their losses will impact the decision making at either place. As a for instance, will Des Plaines feel compelled to produce new etch to replace depleted stock for the gp9 step and louver set? Will P&D return to shows like the March Meet in Chicago? They haven't been to any of the normal shows since Pat's passing. It will be something to keep an eye on.
I have some of the gp9 detailing parts on hand, since I have a goal of someday producing a steam generator equipped Central Vermon gp9.
Central Vermont gp9 by Edward J. Ozog
Let me dig out my stash and see what I have on hand. I'll post photos when I get locate things, and also post anything else I think of regarding the gp9 projects in general.
Jim