Which models are actually heavier? Brass models or die cast metal models?
For me it´s hard to tell if one can generally say that brass models or die cast metal models are heavier.
My die cast metal MTH SP GS-4 for example is much heavier than my hybrid brass & die cast metal BLI T&P I-1a. But I once had a brass Max Gray SP SP-1 in my hands which was definetly by far heavier than the die cast metal MTH SP GS-4.
So can we say that early brass models from the 50s/60s era are the heaviest HO scale engines in general?
I don't think there's really a definite answer to that. Diecast is usually thicker while brass is often made from thinner metal, so the main parts of a diecast model will usually be heavier. A brass model can be filled with more lead weight because of the extra room from the thin metal, so they can be made heavier than diecast with some work. Even a plastic model can be a brick depending on how it's made (like the P1K DL-109).
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I think the old die cast Bowser/Penn Line steam locomotives were, at least at one time, actual lead. I suspect they take the prize.
Dave Nelson
The heaviest engines I've ever held in my hands were brass locos that were filled with molten lead as was done by the owner. The problem with making something that heavy is that it can overcome the motor. There is a point where adding more weight reduces performance instead of improves it, so one has to be careful not to add too much weight.
Assuming my engines are already properly balanced, I do not add any additional weight for the reasons Paul stated above.
I would think that diecast engines such as the ones formerly available from Bowser, as well as today's MTH and BLI engines (select models are diecast) would generally be the heavier engines right out of the box. Brass models that do not have aftermarket weight added will generally be lighter as the metal is thinner.
Today's hybrids have a brass body, perhaps with some weight added, and often a diecast frame. The diecast frame adds a considerable weight component that is not found in today's brass steamers, which typically have built-up frames to reflect the more see-through frames of real steam engines, and which are consequently lighter in weight.
So, my BLI hybrid Great Northern S-2 easily weighs more than my late model (2011 production) Precision Scale/Boo Rim Texas & Pacific 4-8-2. Also, plenty of Key/Samhongsa steamers out there on the used market are lighter in weight than today's hybrids. Of course, Big Boys might be an exception...
John
The question can't be answered definitively unless one compares items imported from the various importers. Generally, plastic is going to almost always come out the lighter of any two comparisons with hybrid, diecast metal, or outright brass. But who would be able to say between any two of those items unless compared in an objective test?
My heaviest and strongest puller, by a hefty margin, is my PCM diecast Y6b 2-8-8-2. It's a veritable beast.