# New Questions re: Bearings ~ I didn't want to threadjack



## CapeCodSteam (Jan 2, 2008)

I have been following Will's thread on heavyweight coaches and bearings. It got me thinking about them a bit more, enough to realize I know nothing.

I am slowly building a consist for my S-12. I about twelve plastic cars from AMS and a few MDC cars. I also have a brass '97 Accucraft wood sheathed boxcar, REA Reefer and caboose. I thihnk if I get any more cars, from now on I'll try to focus on brass ones. I like the SF reefers and the UP double decker stock cars.

As for visiting steamups, due to the lack of space in my tiny car, I'd bring just my loco and the three brass cars. If I need more cars, most of my friends I steam with bring a bunch of Accucraft reefers.

That is the background.

My questions are:

Why do people spend the time and money to install bearings? Is it worth it?

I understand bearings reduce rolling drag considerably, so I imagine it would make sense to do all of them. How does this affect my train? Would it mean the fifteen cars wouldn't be the same workout and I'd have to get more cars to increase the weight?

If I were to start by replacing the brass cars first, what difference would it make pulling just them.

I'm sure there will be more questions as I sort them out in my head and figure out how to word them clearly.

Thanks guys.


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## aceinspp (Jan 2, 2008)

Just replacing with bb makes a big difference as to how the cars roll. You can defiantly pull more cars with less effort. Later RJD


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## Pete Thornton (Jan 2, 2008)

spend the time and money to install bearings 
Kent, 

First, we gotta redefine your question. All your cars have bearings - but they are probably either plain brass or 'engineering' plastic moulded as part of the sideframes. 

Given the previous questions about ball bearings, I'm guessing that's the real question: what do ball bearings do for me. 

From high school physics, you may recall that friction is what slows down a moving object, weight is what makes you do work to lift it, and inertia is the tendency of the object not to want to change speed. 

So, if you reduce the rolling friction, then you only have to contend with inertia and weight. Inertia makes your loco work to get the train rolling, but then if the rolling fristion is reduced, it is less effort to keep it rolling. Weight, on the other hand, is heavy. Reducing rolling friction won't reduce the effort required to pull a 10 car train up a 1% grade. 

In practice on our trains, ball bearings reduce rolling friction by a significant factor, so on a level track your loco can pull a lot more cars (once they are moving.) Even heavy ones - Dr Rivet has a bunch of brass EBT hoppers, and my Mikado pulled 18 of his, one of mine and a combine, all ball bearings, without any sweat. 

They don't help on hills - the reverse if you get uncoupled. In fact, even the wind at Roger's place this weekend was rolling our ball-bearing equipped stock! We were wishing for working car brakes.


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## Greg Elmassian (Jan 3, 2008)

Small correction on the phyiscs: 

Ball bearings will reduce the effort required to pull a train up a 1% grade. But the effort to "lift" the cars up the 1% is almost always much more than the effort saved in rolling resistance. 

There will always be a person who will not agree to this. If you have really bad stock bearings, of course the ball bearings will make such a huge difference that people in this situation will swear they are radically important on grades. 

But if you calculate the effort required to go up a grade, where you are lifting weight (as opposed to flat track), you will see the "truth". 

So a simple rule: on the flat it will make a big difference in getting started and how many cars you can pull. 

The difference between good stock bearings and ball bearings up a grade of any magnitude is minimal. 

So my advice is: If you have plenty of motive power, just make sure your stock bearings are lubed and working right. 

If you are on a "flat" layout, or you are just barely able to pull the load you have in cars, go to ball bearings. 

If you need to pull more cars up a grade, get more "locomotion", double head, etc. 

There are also some disadvantages to ball bearings: 

cheap ones can rust (very few people can afford all stainless bearings) 
sealed bearings have too much friction (the rubber seal adds drag) - (sealed bearings are not same as one with "dust shields") 
they are not good for high current power pickup (locomotive) 
if you do operations, if your sidings are not perfectly level, you cannot spot cars without them rolling away. 

So, there are pro's and con's. 

Regards, Greg


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## BarrysBigTrains (Sep 4, 2008)

Greg,

I buy a lot of ball bearings and I strive to purchase stainless steel. A few years ago they got very pricey so I had to pass and buy just steel bearings. Lately the stainless versions are more reasonable, so I am again purchasing my preference. 



I find that the ss bearings do cost more, but in a worst case they might run about double the price, but lately have been about 20% more.


I buy from Boca Bearings in FL.

Barry - BBT


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## John J (Dec 29, 2007)

As I said in the other thread it made a huge differance in my container car train.


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