I haven't been in the hobby as long as most of you - about 4 years now I think.
I have established a set of buying "rules" for my rolling stock.
#1. No duplicate road names on box cars. No duplicate numbers on any cars.
#2. All box cars have the boxcar red (in some shaded variety) for base color.
#3. All box cars are 40' so far. (may change with new larger layout)
#4. Tank cars are black.
#5. I TRY to buy all steam in New York Central.
#6. I try to keep proto-2 as a minimum for new engines.
#7. All new buildings to be lighted with the MTH Rail King as minimum standard. I love the new WS buildings.
#8. I install red blinking LED's on all structures over the tallest building on my layout. There are only 3 or 4.
#9. No mixing road names for engines with cars of passenger consists. No PRR pulling Chessie for example.
#10. No 0-27 or greatly "out of scale" equipment. One or two exceptions for classic postwar items. (they sit in vignettes on side tracks)
#11. Except for the SP Daylight that I just HAD to HAVE (it is too pretty) all eastern road names.
This may sound a little "repressive" to many of you but the combine effect is to have given my VERY SMALL layout a kind of unified appearance.
The one area where i may deviate is with my "Army Train". I think it might look better with car, after car, after car, EXACTLY the same in appearance. But for now, car int the consist is different. The only commonalty is that somewhere it must say US Army on the car.
I know many of you have "no rules" and buy whatever you like. That is very cool. I'd be interested in hearing from for those of you who have some limitations and what they might be. Mostly because I just love talking about this stuff and am not beyond stealing good ideas. (that is why we are here, right?)
Hey - thanks!