i have acquired a few brass engines that didnt come w/ any weight one of them a hallmark 2-10-4 has less lead in it than a #2 pencil(cant be right) i can find articles on engine balance but no mention of how much weight these or this engine should weight, with the size of the boiler on the 2-10-4 i think i could get pounds into it, anybody know of a rule of thumb or article or charts that indicate how much weight to add?
The NMRA posts suggestions for towed cars based on length, but I don’t recall there being any guidelines over engines. I think most of us would agree that, without getting silly, more weight is most often a better idea. Certainly the best balanced and properly weighted engines in HO are going to weigh between 6 - 8 oz per four inches of length. BLI’s larger engines are about 1.3 lbs and on up, heavier if all metal. Their Pennsy J1 is 1 lb., 9 oz, nicely heavy. I would want a brass equivalent, balanced, to be at least that much, perhaps closer to 1 lb., 14 oz, and if you are handy and want to get lead into all sorts of places, just over two pounds would be great.
Crandell
Fundamental principle, more is better. Tractive effort is directly proportional to weight.
One minor gotcha. The motor ought to be able to spin the wheels. Electric motors overheat, badly, if juice is left on and the motor cannot turn. Derailments, stuff left in underground trackage, and other Murphy’s law events can prevent a locomotive from moving. In this case, the wheels ought to slip. This is not usually a problem, few HO locomotives have enough room inside them to accept so much ballast that the motor cannot spin the wheels.
The locomotive will track better if the ballast is centered.
Don’t know if you have the KCS 2-10-4 there or the Madame Queen but weight should not exceed about 8-10 ounces or excessive wear will result. You might consider contacting Overland Models to see if they have any excess boiler weights laying around, also Sunset Imports and Key Imports. Those are both relatively expensive engines, ($500+), so I would treat them with care as to the amount of weight as well as the installation. While it is possible to add considerable weight to the locomotive I would not reccomend it, they are “not” comparable to the newer “diecast” RTR engines in the weight catagory and were not designed for it.
Mark
A great many of the early Japanese brass were quite heavily weighted, but they also for the most part had very sturdy open-frame motors in them.
I know when I started buying Korean brass, the locos were quite a bit lighter, and also seemed to have rather light, underpowered early can motors in them. I remember several Custom Brass locos I bought that were very light, and when I put in additional weight, it seemed to shorten the life of the motors. I was able to cure that by replacing the early Canons with heavier-duty NWSL cans, and the result was a much smoother, more powerful locomotive.
I’ve found that the trick is not to add a LOT of weight in the boiler, but to make sure that the weight you DO add is spread out and properly balanced over the drivers. A rule of thumb that seems to work for me is to slip a pencil between the middle drivers, and if the loco balances pretty well, then the weight is probably well adjusted. I generally use sheet lead, which can be curved and fitted into the boiler cavity.
But like Mark, I would caution against TOO much weight in Korean brass unless you plan on replacing those earlier can motors with more dependable newer ones like NWSL.
Tom