Lots of truth is many of THE ABOVE REPLYS I think what Allan said in the last part is really good advice for anyone trying to put some limits in place.
Allan Said "
One suggestion I frequently offer to others is to closely focus one's interests to a particular road name or two, a particular era or region, or something else that helps to restrict the urge to purchase in a wildly random manner.
I try to follow this with the CN/GTW & SANTA FE Engines. Also I only use DCS no Tmcc or Leagcy so it restricts me to MTH Engines. Rolling stock is another issue all together so I do not do any Automated Cars, no Beer cars,only boxcars to match my 3 prime roads, no reffers,no cattle cars,no space cars. no Army cars.
I do like a lot of cars of particular kinds.
Like Passenger cars to match my 3 Primary roads. Even here in Passenger cars I do limit my ATSF to the streamline 21" made by k-Line and no other Mfg's and no Heavey weights. In my Cn I do both Streamline and Heavetweights but only use GGD & MTH cars. In GTW Passenger cars I only do the Heavyweights by GGD & MYH.
I alsp like Coal cars but limit my self to the one style Bathtub GondolaBY MTH & LIONEL.
I also like Ore cars but find them very difficult to find the road names I like so I broadned out my quest with some of the Canadian Road names which fit with my CN power. I have CN, CP Rail, Ontario Northland, GTW & DM&IR.
Amother class of Car I like aare the Grain cars. So I follow my 3 Principal road names CN, GTW & ATSF for the vast majorty of the grain cars. However since I do have a large grain milling operation on the layout I do have a couple of cars each in many road names to add a little variety.
Another class of car I like are the TANK TRAIN CARS by Lionel.So I do have the White CN cars, The Black Cibero cars, black NS with White letters, the Black TANK Train cars with Orange letteringamd no other Tank cars.
I have some intermodal cars mostly made by K-Line but a few by Lionel and MTH.
So even with restrictions I probaly have TOO MANY TRAINS