The height of freight cars can vary tremendously, but passenger car heights were very consistent in late steam/early diesel times. Most heavyweight cars, including the Pullman Co.’s standardized sleepers, measured 14 feet from the rails to the top of the roof. It’s important to me to know that Atchison, Topeka & Santa Fe heavyweights were generally about 14′-3″ tall, and if your favorite prototype’s cars were a different height, by all means use that dimension. Lightweight streamlined cars were, if anything, more standardized, and almost all of them measured 13′-6″ over the roof.
You’ll find, however, that many models, especially older models in both plastic and brass, ride higher than they should. Most often they were manufactured that way to allow for extra truck swing on sharp model curves. But it’s easy to see that full-length 80- or 85-foot HO passenger cars look their best only on curves of 30″ radius or even larger.
If you build your layout to that standard, you can let your passenger cars sit down a little lower on their trucks, and the trucks will still have all the swing they need. The cars will look better in profile, forming trains of matching height, and individual cars will appear better proportioned and not jacked up off their wheels.
(If you want to model double-decker cars like the Santa Fe’s Hi-Levels or the many varieties of bi-level commuter equipment, you’re on your own for dimensions. My advice, though, is to learn what height those types of cars should be and adjust your models accordingly.)
The most effective way to lower a car is usually to modify the body bolster. On plastic cars such as the Rivarossi heavyweights, you can use your caliper as a depth gauge to measure the height of the bolster from the car floor (looking at it upside-down), then subtract the amount you want to take off the car’s height to see what the height of the bolster should be.
On the Rivarossi cars, I like to shave off the round boss on the bolster using a no. 17 chisel blade and fill the kingpin hole with a piece of 1/8″ plastic tubing long enough to serve as a kingpin or truck-mounting boss. Then I add a square styrene plate of whatever thickness it takes to bring the bolster up to the needed height – laminated from different thicknesses if necessary – with a 1/8″ hole to fit over the tubing. The tube can be tapped for a 2-56 machine screw so the truck is easy to remove and replace. The side bearing pins at one end of the car can either be trimmed to the new bolster height or removed entirely.
One other point about the Rivarossi cars: I generally keep their original trucks, which look very good, but replace the wheels. The stock wheels are only 31 scale inches in diameter, but 36″ wheels were the standard for almost all passenger cars. You’ll need to shave the faces of the molded brake shoes with a no. 11 blade to let the larger wheels turn freely. And remember to account for the effect of larger wheels (36″ – 31″ = 5″, 5″ ÷ 2 = 21⁄2″) when you decide how high to make the modified body bolster.
To be sure, I don’t get the perfect car height every time, but I try to ensure that if I err it’s on the low side. I can always add washers to shim the car up – Kadee fiber washers fit over the 1⁄8″ tube – but that won’t work in the other direction.
For slightly different approaches that have guided me, see part 2 of Bill Darnaby’s article, “Kitbashing heavyweight Pullman cars,” in the May 1989 Model Railroader, page 104; and John Pryke’s article, “Improving HO scale freight and passenger trucks,” in the November 1998 MR, page 115. These articles are available in our online archive of magazine issues.
From The Model Railroader’s Guide to Passenger Equipment & Operation (Kalmbach Books, 2006).