I cannot speak for any Access-based programs, but RailBase Professional by Albion Software is great for cataloging rolling stock and structures. I've been using it for about 10 years.
You can even tie it to their ShipIt program to generate switch lists, etc. Check it out at http://www.albionsoftware.com/.
Regards,Greg
Greg Shindledecker Modeling the =WM= Thomas Sub in the mid-70s
Forget Microsoft Access. I had a train program I made with it too but wasn't happy with it. I downloaded the free software "Yard Office" and it works great. Much better than any access software I saw out there.
http://www.musicmixradio.com/yardoffice/download.htm
I'm not sure about accessories, but I'm sure you could work it somehow with this program.