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RichM
22nd Jul 2017, 11:34 PM
When is there too much weight or is it a more trial and error when adding more weight to a Loco 'aka my Shapeways Boxcab using the Bachmann 44 tonner as the Mech Thanks

SteveG6942
23rd Jul 2017, 10:35 AM
From my experience with the 44T I could pull 16 cars on flat ground and 10 cars up a 2% with it. How many cars you looking to pull?

Mac
23rd Jul 2017, 11:07 PM
I was going to say "one guide would be what other locos use the same motor and how much do they weigh (I know there is more to it than that -- like gear ratios etc...) but seems like something easy to check. For example, Bachmann F3/F7s use the same motor as their substantially heavier cousin the E60CP." However, looks like the 44 Tonners uses a really tiny motor that may not be used in other units.

gary60s
24th Jul 2017, 09:08 AM
Back when I was selling powdered tungsten, I did a lot of research on adding weight to locomotives. I came up with this guideline:

Too much weight added to a loco can cause too much motor strain. Newer locos have motors that are more tolerant than older ones. It is best to test a loco with temporary weight added. 22 inches of .118” diameter solder weighs 1 ounce (11inches is ounce), and is an easy way to drape test weight over a loco. If loco gets hot, you’ve added too much weight. If you have a current meter, place it in series with a track lead and check current draw with no weight added. Then check current as you add test weight. If you notice more than a 20 to 25% increase in loaded current, you should stop there.

You should weigh your loco before adding weight, and not add more than 15% of initial weight. Tungsten is a conductor and should be insulated from motor parts, circuit boards and exposed wiring.

P-LineSoo
24th Jul 2017, 02:55 PM
My limited amount of experience with adding weight proved, for the most part, fruitless. The answer - for me anyway - was buy better locos and read Spookshow's reviews before buying.

NtheBasement
24th Jul 2017, 03:30 PM
I was disappointed when I converted locos to dcc because the milling out of frame material caused them to no longer pull the same load as before. I added weight and it made a big difference.

The key is add weight to the light end of the loco. Find the fore/aft balance point on your loco; its never half way between the trucks, you will find one end is heavier than the other. When you add weight, add it someplace between the trucks or to the light end of the loco. If you add it to the heavy end of the loco it will backfire by teeter-tottering the far truck up. The less weight on a truck the sooner it will slip, and once one truck slips the other will too.

RichM
25th Jul 2017, 01:20 AM
Back when I was selling powdered tungsten, I did a lot of research on adding weight to locomotives. I came up with this guideline:


I still have a bunch of the powder I got from you.....lol

randgust
15th Aug 2017, 03:52 PM
It's significantly trial and error. Weight is twofold, one is to increase tractive effort, the other is to improve electrical pickup. Adding weight and not overloading the motor will gain you performance improvement just in consistent pickup, and in that light, more is always better. The Hobson's choice here is that DCC is far fussier about electrical conductivity than DC, but to get it you have to remove weight somewhere.

If you're adding weight and and then loading it up to full-slip to pull a longer train, you want to monitor motor current, easy way is with your fingers feeling for heat - before and after. You really have to work in N scale to get enough weight to actually overheat a motor, as even with traction tires, you'll only get maybe 20% adhesion on the rail. Not that it can't happen. I finally found out that I could get a Kato 2-8-2 genuinely HOT with a GHQ L1 pewter conversion boiler and tender, pulling about 30 cars uphill a 2.5% grade for 20 minutes or more. It's still my traction champ, but I monitor it closely.

The thing nobody seems to 'get' is that not only have the DCC frames been cut out, and cast out of a non-lead lighter alloy, but the wheel material is a harder, slicker alloy that often gets less 'grip' than conventional brass but gets better electrical contact - specifically a problem with Atlas. My testing has proven that it's not particularly uncommon for a newer, DCC compatible unit to have only 1/3 the pull of it's 80's predecessor - in this case the Atlas GP38 vs. the 1982 Kato GP38. In those cases, you've got a good, solid motor, you will run out of space to put weight before it's a current draw/heat problem. I don't think Bachmann is as bad - I've actually had better results with their Spectrum on performance analysis. I'm a fan of the 44-tonner drive for sure.

I took a Bachmann 44-tonner frame and used it for my own 70-tonner kit, and made a conversion cast weight out of Type 160 low-temp that filled up all the space where the DCC board once was, and the entire cab area. About doubled the weight of it. I just use it for light industrial switching, not drag use, but it is now electrically bulletproof. No difference in heat. If you are DC instead of DCC, look at removing that entire board and replacing it with metal - just insulate the top of the frame with some tape so it won't short out the frame halves. The frame also doesn't fill the cab area, that's another opportunity for weight. It's a good 8x8 drive and pickup system, yes its a small motor, but mind the heat/current and you'll be fine.

Steam is another matter entirely, because some locomotives are incredibly unbalanced - like the Walthers/Life-Like 2-8-4. With the traction tire on the rear, if you add weight in the cab it will literally jack the lead axle up and create a derailment problem. Pile all you can in the front and stop, you'll again run out of space. The Atlas 4-4-0 is just the opposite, it's very nose heavy, and if you add a cab weight it's a silver bullet greatly improving traction and electrical pickup.