Right now, we're getting excited about "heritage units". It used to be that we had the railroads, not just one unit painted in that scheme.

Take the 1960s. In the area of motive power, in 1960, UP 844 was still on the regular roster. GP9 production had just stopped at LaGrange (a few units were produced in Canada in the 60s). GP20 production had just begun. Alco was still producing units. FM was no longer building engines, at least not in the US, but you could still find units in common use. By the end of the 60s, we gone through SD24s, GP30s, and Big Blow turbines, and EMD was producing SD45s and DD40s. GE had joined the party, and had gone from U25s to U36s and U50s.

In the last 10 years, we have gone from the SD70M to the SD70ACe, and from the C44-9W to the ES44AC. Somehow it doesn't feel the same.

In the 1960s, there were maybe 30 Class 1 railroads, and over time, you'd see cars from all of them. Now there are 6. In the 1960s, you had names like "Chesapeake and Ohio" and "Atlantic Coast Line". Now you have "CSX", which might as well be the name of a computer chip.

In one place there is now more variety. In the 1960s, you'd occasionally see small, discrete graffiti, in chalk, from people like Bozo Texino. Now it's car after car of spraypaint graffiti, from people with more ambition but much less taste. But that's only an improvement if you like watching graffiti, rather than trains...