MTH Madison Cars: Premier 70' vs Railking 60': How are they different?

MTH Reading & Northern 60' Madison Coach Car #30-69353- Plastic body only, without vestibules, measures 14 3/4 " long. Don't have any 70' to compare

Length is a difference but also premier cars have more detailed sprung trucks. Also, I don't think the railking cars come with passengers.

The Rail King streamliners and heavyweight cars (and their Lionel clones) are 48' long.  Same size as a Chicago L car.

The Rail King 60' cars are the same length as Lionel Extruded aluminum streamliners and Lionel Madison cars.

ArtsModelTrains - Correct.  Premier cars have passengers and the Railking don't.

I have a couple Railking in my Chessie Steam Special consist and they don't look out of place even though they are shorter.  It does have a vestibule and solid trucks (not sprung).

In the video below, the Railking is the 3rd passenger car (the others are Williams that I added vestibules to).

There is more than length to consider when determining how "big" a locomotive or piece of rolling stock is. There is also width and height - in essence, the girth of the piece. Some less-than-scale equipment (MTH, Lionel, etc) is compressed in length but not much in girth, so these pieces can live among 1:48 equipment pretty well. Lionel PW and PW-clone extruded passenger cars are some of these. On the other hand, the "scaled down" (a scale, but not 1:48 scale) RK pieces can look like what they are: undersized.

I have some nice RK Heavyweights that look quite acceptable behind 1:48 locos, but a little inadequate next to, or mixed in with, the Premier or Lionel Standard O stuff. They do not look awful, though.

It's case-by-case, I'd say. Not just length.

Thank you all.  I'm going to go ahead and order the RK heavyweights.  This has been very helpful.

Another salient point; RK cars will run on as small as 031 curves. Whereas Premier cars need 042 minimum.

I had some Premier passenger that I had some issue with the center roller, so I bought a RK Chessie for truck donors. Did not work, the couplers would not reach far enough, and wires not long enough for something.

Then later on I figured out it was just a bad center roller, AND, MTH sells them.

Just saw your post and that you already ordered. Older streamlined RailKing 60' and Premier 70' GN passenger cars.  Car bodies height and width appear to be the same. Details are a little different. Neither has sprung trucks nor people.  If these were rolling down your layout, would you really notice?  I've never owned a 60' Madison car so cannot really say. The 12 inch RK Madison cars look stubby to me - again same body width and height.

That said I have Weaver 20 inch cars and they look great and I like the extra time it takes for the car to move past my eye.  I had not noticed the paint job difference on these until I saw this photo.