Does gallium weigh as much as lead?
One pound of gallium weighs the same as one pound of lead. However, one pound of gallium will take up more space than one pound of lead. And your gallium will melt at 85 degrees or so, so it may be messier than lead.
It depends. One gram of gallium weighs the same as one gram of lead. One mole of gallium weighs 69.72 grams, one mole of lead weighs 207.2 grams. So what you really want to know is which metal is more dense.
Greg
Can you go to your local bait and tackle shop and buy gallium fishing weights?
To expand on that, just look at a periodic table. It shows how lead is much heavier than gallium due to lead having the higher atomic number. Gallium though if you want a heavier material is certainly more heavy than iron, zinc or aluminum; and although not as heavy its certainly cheaper than platinum or gold. https://pubchem.ncbi.nlm.nih.gov/periodic-table/
Just make sure to wash your hands after working with lead, and especially be careful if milling it since lead can be risky for your health; but as long as you are taking the proper precautions it is the heaviest and most importantly cheapest at it material you can find on market.
Unless you want to give depleted uranium weights a try or something outlandish like that. 
Tungsten is denser than uranium. Depleted or not. So is gold.
Gold is very easy to work, a definite plus. Tungsten is very difficult to work, a minus.
I’d go with gold.
That said, if you’re the kind of guy who’s always trying to save a buck, I’d go with lead.
Ed
Lead is about twice as dense as Gallium. Gallium also has a very low melting temperature, which is why its NOT recommended to be placed in locos as weight. If your motor heats up even a little it could be detrimental.
Charles
Considering certain other problems with gallium, including its behavior with aluminum and other metals and alloys, I fail to see what point there could be in using it in combination with some denser material actually suitable for locomotive weights, for what I presume would be some sort of formable weight like dental amalgam.
Gallium in europa est.
Germanium in europa est.
Gallium et germanium in europa sunt.
Desculpa me por favor. No me podia ayudar.
“Weight” of a given number of atoms of an element (usually calculated per mole) is not a function of the density of the elemental substance. Likewise, atomic number also isn’t necessarily proportional to the weight of a given “quantity” of the element. A mole of radon takes up a lot of space. The weight of a given “quantity” of a metal element will depend upon its structure as a solid (assuming you intend to use it as a weight that needs no container).
No.
A cubic inch of gallium has less weight than a cubic inch of lead. The very first response in this thread was the correct answer.
-Kevin
Jim Fitzgerald’s N Scale Cotton Brute set drawbar pull records - weight was depleted uranium.
Given the weight of lead compare to most other metals, the ease with which it can be re-shaped, and its relatively low cost, why would you bother using anything else for weight in your locomotives or rolling stock?
I asked at a local tire outlet if they had any used wheel balancing weights that I could buy, and got 10 or 12lbs of them for free.
It turned out that they weren’t all lead (some appeared to be zinc and others were steel, but there were lots of lead ones.
There’s a thread HERE showing how to cast your own lead weights.
Wayne
I bought sheet lead off of Amazon in 3 thicknesses: 1/64, 1/32, 1/16. Quite a bit of it, actually.
I recommend that approach. I just cut out my pieces and stack them up.
Tungsten is available (so is fake tungsten, so be careful) in shapes and powder. You, practically speaking, CAN’T shape it, so you glue it in.
Ed
But that first response was a different answer to yours. That first response was, presumably, intended to focus the thread on the actual question asked rather than just the literal question.
Obviously the OP was asking about density, not mass. That’s what matters in our hobby because the maximum usable volume for weights is the relevant limit.
Weight is of course a relative term with several connotations which is why chemists and physicists prefer to use the term mass instead of weight when making these comparisons. Weight when used in the context of “heaviness” means mass at sea level for a given volume of material.
Will it sink or swim.
I use lead shot from a diving bag to make weights (for whatever reason, it was cheaper to get a 5lb diving bag than 5lbs of lead shot). The lead shot is easy to melt and form without taking up much space compared to other metals, so as long as it’s handled carefully, it’s a very useful metal.
As others have said, gallium has too low of a melting temperature and density to be useful on railroads, unless you’re modeling a hot metal facility that needs liquid metal to look good.
Hmm…
I’ve saved out a whole pile of mercury light switches, from Olden Tymes. Since I already made a “silver” penny, maybe I’ve got a use for it/them.
Ed
PS: Gallium melts at 85.57F. So, not only might a motor in a locomotive cause it to melt, so might Florida or Texas.
I used to pound fishing weights flat, then I bought the sheet lead like you described. An old paper cutter from a thrift store cut it into sections that fit in HO cars easily.
I also recommend this approach.
-Kevin
Paper cutter is an excellent choice. Scissors work well, too.
Tinsnips are NOT necessary.
Ed