Adding Weight


Still here... lurking
***This is a replacement to my traction tire thread***

Where is the best place to put weight on the Bachmann SP GS-4? I saw a video of an NKP 765 pulling 60 cars on a 1% grade and I would like to know where and how is it done?
It doesn't matter so much where you put it as it does getting the weight centered over the drivers including the loco weight itself. Balance is important.

Fit it into any available space giving clearance to the various parts also hidden in the loco.

Don't over do it. Add some - test pulling power and motor current- if current is within the specs for the motor add some more - test again and so on.

Used to be some special lead-bismuth compounds for this that had a melting point a little below the boiling point of water. Think one was called Cerro-Safe (because it would not explode if you got some of the boiling water on it). It could be poured in and any excess removed with a Dremel tool. Keep in mind this method can get a loco insanely heavy if carried to the extreme (sez he who did just that with a HO DM&IR 2-8-8-4). I even removed the relatively small DC motor in the firebox and replaced it with a Pittman DC-91 in the tender. I filled the entire boiler with the stuff - had to easily weigh 10 pounds or more. There was also a 2:1 gear reduction in the tender so it ran much closer to prototypical speeds.

Lead sinkers can be used if beaten into the proper shape. DO NOT melt lead - its melting point is too high and will explode in contact with water. It also might un-solder every joint on your fantastically detailed brass import, lol.

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Thanks for the reply, Ben. I saw on the Bachmann Forums someone put lead pellets in the domes of the engine then used "lead bars" bent into shape and stuck parallel to the boiler. My Daylight is pretty heavy for an engine, so I don't know if it has too much weight because it slips a lot. :confused:
Yes - lead pellets (bb's or shotgun shot) is a good choice. Can be selectively placed (glued) in different locations a little at a time and is far easier to remove if necessary. Allows you to keep the locos balance and "sneak up" on the motors current limit.

Some of that slippage is almost certainly due to shiny smooth drivers of equally shiny and smooth rails, lol. Other then traction tires (which I detest) not much you an do about it.

Back in the age of dinosaurs when I got into model railroading pretty much all brass locos came with (an easily removable) weight in the boiler. Cast locos like those from Mantua and Tyco didn't need weights. They were automatically quite heavy.

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Okay, so I went to the store and got 3/4 inch lead sinkers, and I am going to bang 'em out flat. Should I glue them on the top of the boiler, or on the sides? Also, can I hot glue them, or would that melt the shell?
Actually I would use a rubber band and just attach them to the outside of the loco and test the current draw that way. Once you get the current maximized without exceeding the motors specs then pound away and install. Might save you a bit of work. Who cares what it looks like while testing, lol. Easily adjusted this way too. Depending on the design of the loco it might even be possible to just sit them on top while testing. No muss - no fuss.

I have no experience with locos other then those made from brass. Hot glue might work but are you sure you want to take the chance? I don't know hot it gets or what the melting point of the plastic (if that's what it is) might be on your loco.

Caution and thinking ahead is a good idea. I don't think epoxy is a good choice as it would be difficult if not impossible to remove if that ever became necessary (it certainly would work). Ditto normal plastic glue. You don't want to use something that will mess up (melt) your loco. Crazy as this might sound - I'd try Elmer's white glue (sparingly when the time came).

Perhaps a bit of experimentation is in order. Its been my experience Model Railroaders always have several different kinds of glue here and there. We are a sticky fingered lot (don't take that wrong, lol).

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So I talked with my dad, and he said to put the weight on the flat spaces by the motor, not in the shell. Would that interfere with the current?
(Sorry for so many questions, I've never done this before.)
I think what your dad means is do not glue the weights to the shell (good advice). Anywhere on the (probably metal) frame is fine. As long as the weight is not touching the motor or any bare (unlikely) wires is ok. It's ok f it touches the metal frame. If you do place it in the wrong location (electrically speaking) you will get an instant short circuit which will be equally instantly obvious, lol.

If I was doing this I would take the shell off, place the loco on the track , carefully place weights on it (one at a time in different locations), then very slowly and carefully give it some power. If you have a short you will immediately know and can move the weight as necessary. Once you determine the best locations and how much to add - then carefully glue them in place. Don't over do the glue.

Just think ahead, go slow, and don't overload the motor. Sometimes finding a replacement can be difficult.

BTW - assuming you bought this new you should have gotten a data sheet with it which will (well its supposed to, lol) tell you the maximum amount of current the motor is designed to draw. DO NOT EXCEDE THIS VALUE!