Where to add weight to an HO-Scale Bachmann Spectrum F40 loco?

[steveeusd]

Hello Everyone--

I have an HO-Scale Bachmann Spectrum F40PH and want to add a little more weight to it (6 ounces to be exact).  I added 2 ounces by filling the fuel tank with lead.  I would like to add 4 more ounces; but, I don't see where more weight can be added.  The chassis fits snuggly against the shell.  No room there.  Very little space exists between the top of the motor/circuit board and the shell's ceiling.  I don't want to place lead weights near a decoder or on the ceiling.  Any ideas where or how I can add more weight?

Thanks,

Steve Williams   

[rogertra]

Hello Everyone--

I have an HO-Scale Bachmann Spectrum F40PH and want to add a little more weight to it (6 ounces to be exact).  I added 2 ounces by filling the fuel tank with lead.  I would like to add 4 more ounces;

What exactly are you hoping to pull with this loco?

Do you want to pull down house walls? 

[Jim Banner]

Short of putting some of the lead on top of the roof, I don't think you will be able to do it without modifying the inside of the locomotive.  That would involve removing the drive tower from one of the trucks, reducing the locomotive to 2 wheel drive.  If you are looking to pull more cars, that would of course be counter productive.  A better modification of the locomotive would be to turn grooves in a couple of the wheels and add traction tires.  This will reduce the reliability of the power pickup but will increase the traction considerably.  As with adding more lead, adding traction tires may cause your locomotive's motor to overheat and burn out.

Assuming you want to pull more cars, there are other ways of doing it.  One is to reduce the drag of the cars you are pulling.  If they have six axles, pop out the centre axles of each truck.  Four axles are less drag than six and nobody will notice the missing wheels.  Then ream the remaining 8 journals and lubricate them with graphite while reinstalling the wheel sets.  If the wheel sets have plastic wheels, replace them with metal wheels and make sure the wheels are truly round.  I am assuming you have Delrin or other slippery plastic trucks - if they are styrene, ABS or other cheap plastic, or worse, metal, replace them with Delrin trucks.

Next is to reduce any grades you might have.  If you want to pull as many cars as the prototype, then you will have to stick to prototype grades, say 1% or less.  While you are at it, increase the radius of the curves in your tracks.  You will not be able to use prototypically large curves, unless your layout is in a warehouse (don't we all wish!) but increasing curves from 18 or 22 inch radius to say 30 or 36 inch radius will help.

If your locomotive still cannot pull enough cars, try lightening them.  Usually we make our cars heavier for bettery trackability, but if you have wide curves and smooth track, you can lighten the cars and still keep them on the rails.

These steps would require a lot of work and in the end your locomotive still might not pull as many cars as the prototype.  Another alternative, one used by both model railroaders and real railroaders when they cannot pull enough cars, is to add another locomotive.

[Yampa Bob]

I don't understand the obsession among modelers with "pulling power."  I have 4 Bachmann GP35 and GP40.  I have not added any weight to them, but a single loco will easily pull 30 to 40 cars at a scale speed of 80 mph or greater. 

Since I have a small layout, I couldn't put 80 cars on the tracks, but I'm sure that 2 locos could pull them with no problem.  With easy rolling cars, 3 locos could pull 100 cars, provided there is sufficient power to the rails. I consider a car as easy rolling if it will quickly coast down a 1.5% grade by itself. 

When the coal trains come through our ranch, there are usually 6 or 7 locos pulling 100 loaded cars. That equates to 10,000 ton of coal, or about 1400 ton per loco average.

Ok, let's do a bit of math.  Say you have 100 HO cars weighing 5 ounces each, which is a bit high, the average is 4.5 ounces for my shorter cars.  That's a total of 500 ounces, about 31 pounds. Scale that up to full size, that's 10,000 ton. And that's EMPTY.  As Jim noted, you can lighten the cars if your trackwork is near perfect, and as seen in the math, we often overweight our cars.

The scaled down weight of a diesel to HO comes out to about 9 ounces, yet my GPs weigh 13 ounces out of the box. Start weighting them to 20 ounces or so, and you can create a strain on the drive train and excess heat in the motor.  I consider wheel slip as normal and prototypical. 

If I can pull 100 cars with 3 locos, that comes out to 3300 tons per loco full scale, more than twice the loading factor of a real freight train. However, real railroads don't pull 100 cars with only three locomotives.

UP doesn't use those 7 locos just for power, it's for fuel economy, less coupler strain, better dynamic braking, less heating of traction motors, and overall longevity of expensive locos.  When the coal trains come through they are almost idling at 60 mph.

While visiting the Colorado Railroad Museum last week, I bought an exciting 2/DVD set called "Rio Grande Odyssey", over 2-1/2 hours of nonstop action, from steam to diesel in the 90's.  My favorite segment is of 9 GP40s assisting a freight train up  Tennessee pass.  Once at the top, the 9 locos go back down to assist another freighter.

Throughout the DVD, I was surprised at the number of locos used for short freight trains. It's a "Green Frog" production, I highly recommend the set to anyone who likes freight train action, especially here in the mountains, where grades are as steep as 4.5 %.  In one segment, you can barely see the cars for the smoke coming from the brakes.

Back more to the topic at hand, if your Bachmann loco, steam or diesel, can't pull at least 30 cars, then you need to tune your rolling stock.  If the drivers are slipping on a flat track, you might have oil on the rails.  If the drivers slip on a grade, add another loco as a helper.  The helper can be a powered box car, water car, caboose or any other powered freight car.

[rogertra]

Ok, let's do a bit of math.  Say you have 100 HO cars weighing 5 ounces each, which is a bit high, the average is 4.5 ounces for my shorter cars.  That's a total of 500 ounces, about 31 pounds. Scale that up to full size, that's 10,000 ton. And that's EMPTY.  As Jim noted, you can lighten the cars if your trackwork is near perfect, and as seen in the math, we often overweight our cars.

Bob.

You cannot scale mass or friction, therefore relating the weight of a model train bears no relationship to a real one.

Why do we weight our locos?  For the simple reason our freight cars do not roll as easily as real ones and because we usually tend to have steeper grades and far steeper curves than prototype railways.  To pull a prototype looking train up our steeper grades, we need that extra bit of weight.

Adding weight to a model diesel is usually not required as a model diesel will usually out pull the prototype.   Steam however, is a different matter.

Almost all model steam locos require additional weight but this weight must be added in the correct places to maintain, as far as possible, the centre of gravity centred on the centre of the drivers.

A prototype 4-6-0, for example, may be able to pull 20 freight cars on flat terrain yet how many model railways have enough room to run 20 car freights, behind a 4-6-0, on a completely flat railway?  Not many of us.  So we have to compomise.  To enable our 4-6-0 to pull say 12 cars on our model railway, with 2% grades, we must weight it so that it's able to handle a train of that length and still look realistic while doing so.

How many model steam locos can pull 100 car freight trains (Without awful traction tires)?  No many, yet a 2-8-2 should be able to do that so that's another rseason to weight them.

[Yampa Bob]

Roger
I agree that it is difficult to scale friction as it relates to rails, wheels, axles, and bearings.  However you most certainly can scale mass, therefore you can, in a rough sense,  relate the weight of a model train to a real one.  Otherwise, Newton's laws are invalid.

In my example I used "weight" as a scaleable factor.  In most situations, by disregarding any differences in the Earth's gravitational field in different places, or for places far from the surface of the Earth (such as in space), the terms "weight" and "mass" can be used interchangeably.  Since the weight of an object is proportional to its mass, it is unproblematic to use "weight" for both concepts. 

Knowing how particular you are about being prototypical, I'm puzzled about your statement that a 2-8-2 should be able to pull 100 cars. Perhaps that is true, but is that prototypical of a real railroad?  As you once told me, I don't know much about real railroads, but as an engineer I do know about the physical sciences that applies to them.

As I mentioned above, a 200 ton locomotive scales down to 9 ounces.  But since my locos weigh 13 ounces, there is no need, for me at least, to add extra weight.  However, modelers are free to do as they like, it is after all their railroad, not mine. 

For the record, I'm not debating this issue, merely relating facts as they apply to my railroad.  Incidentally, I have a Bachmann GE 70 Ton that I chopped and lowered the hood, and am running it without the factory weight.  At only 5 ounces, I have pulled as many as 20 cars with very little speed reduction. 

[Jim Banner]

Let's see now.  One hundred cars at 120,000 pounds gross weight each is 24,000,000 pounds total.  Divide that by 87.1 cubed = 36.3 pounds which is pretty close to Bob's calculated H0 train weight of 31 pounds.  If we divided 36.6 pounds by 100 cars that would be 5.8 ounces per car, not a whole lot more than Bob's 4.5 ounces.  (NMRA recommendations for a 50' car, full or empty, is 4.5 onces.)  I would say that weight scales pretty well.

Friction, on the other hand, is hard to get realistically low in small scale.  A 4.5 ounce car rolling (but not accelerating) down a 1.5% slope is being pulled by gravity in the amount of 1.5% of its weight.  Make that 100 cars and the force pulling them is 1.5% x 4.5 ounces x 100 cars = 6.75 ounces.  A locomotive pulling the same cars on dead level track would also have to apply a force of 6.5 ounces.  Let's compare that with a real train.  In the real world, cars with roller bearings require about 5 pounds per ton of weight to keep them moving quickly along.  So our 1200 ton train with need a force of about 6000 pounds.  Scaling that down to H0 gives .15 ounces.  Oops!  Looks like the friction really did not scale down.  Maybe not surprising as Bob's cars take a grade of 1.5% to keep rolling while a real car with roller bearings will keep rolling on a 1/4% slope, once it has started.

The other thing that comes out of this is that if a model locomotive pulled in scale, our model train would require 6.5 / .15 = 43 locomotives to move as many cars in H0 as a real locomotive could move in the real world.  This surprises me, even after checking and rechecking the numbers.  But maybe it shouldn't.  A strong man can push, by hand, an empty car on a level track, once it has been started in motion.  (This difference in friction also explains why it is all but impossible to do a flying switch or a dutch drop in H0 scale.)

[rogertra]

Bob.

On flat land railroads, a 2-8-2 pulling 100 cars is quite possible.  However, a train of that length would probably be pulled by something larger, a 4-8-2, 2-8-4 or a 2-10-2 etc..  Railways like the Nickel Plate Road typically ran 100 cars behind 2-8-4s.  Even an 0-6-0 or definitely an 0-8-0 switcher can move 50 to 100 cars.  There is no formula that will tell you how much a steam loco will pull.  There is a theoretical formula for tractive effort but theoretical tractive effort doesn't translate into real world action.

The normal formula used (for a 2 cylinder locomotive) is:

TE= cPd2s/D

where

t is tractive effort
c is a constant representing losses in pressure and friction; normally 0.85 is used
P is the boiler pressure
d is the piston diameter (bore)
s is the piston stroke
D is the driving wheel diameter

However, this is a theoretical calculation and many a steam loco has not lived up to this potential as other factors also come into play.

And as Jim states, one man can easily keep a 100 ton freight car rolling once it's moving.  However, four or five guys can easily get a 100 car to move just by pushing.

I've personally, with the other three or four crewmen, pushed cabooses out of the way with no other assistance.  Ditto for the freight cars.

[Yampa Bob]

For the past year, I have devoted over 2,000 hours of research and study regarding real railroads, as pertains to "when steel meets steel".  I am not concerned about prototypical issues such as what railroad pulled what car, etc.  I am concerned only about the dynamics of railcars, the wearing of rails and wheel treads including spalling, resultant forces in turnouts, and all such issues that occupies an engineer's mind, and  someone who has a large investment in UP stock.

Granted, I have not studied the theoretical equations pertaining to steam locomotives, and have no interest in such other than interesting reading.  I am satisfied that my Bachmann Connies and Roundhouse vintage locos will pull all my excursion cars, which is their sole purpose on my layout.   

However, by applying physical principles and dynamics pertaining to real railroads, I can say all my locos and cars run smooth and rock solid, and I have solved most derail issues. I am a happy railroader.

I read somewhere, in an AREMA article, that a freight car loaded to its rated capacity has less rolling resistance than an empty car.  It was explained that as the rail/wheel compresses (flattens), weight is distributed over a larger area.  I have no problem with this concept, it's about pounds per square inch of pressure. The lighter the footprint, the less resistance to motion. (once starting inertia is overcome).

Keeping in mind that inertia applies to objects at rest or in motion, that same strong man could keep a fully loaded car rolling, once he got it started. In fact, at some point he might have to move more quickly to keep from being run over by the car.   

Some physical characteristics cannot be scaled down or measured, such as the relative hardness or elasticity of rails and wheels.  Real rails and wheels suffer extreme wear and must be replaced at some interval.  Frog points are damaged from the hammering of wheels, rails are forced out of guage.  So...will our rails and wheels ever wear out?  It is possible that our rails and wheels are much more durable in relation to our car weight, than real rails and wheels are in relation to imposed weights and forces.

Jim:  I watched a flying switch on my DVD, it was incredible to see a caboose roll very slowly about 100 feet to silently engage the couplers.

I think every true modeler is a fanatic about one issue or another, such as detail, weathering, rail code, etc.  While playing the game of railroading, I have to follow my best suits of knowledge.  In short, I am more concerned with performance than appearance, which seems to be the UP code.   

[Yampa Bob]

Jim:
I neglected to mention that my 1.5% rolling test is conservative.  Some of my better cars will roll very slowly all the way down a 1% grade, but I have to give it a gentle nudge at the top to overcome standing inertia.

My test track is a 3 foot length of flex track mounted on a 1 X 4.  I also use the track as a "dead start grade pull test", using heavily loaded gondolas.  I won't bore anyone with results, except to say no one can tell me that Bachmann locos don't have good pulling power.

One of my future projects is to build a progressive weight sled, similar to those used in tractor and truck pull contests.  Yup, the mind of the "Mad Scientist" never rests. 

[rogertra]

What we are all hoping for, or I am anyways, is the freight car that when given a slight shove at two to three scale miles per hour, will continue to roll at two to three scale miles per hour, over level track, for several hundred scale yards.

Then, finally, we will be able to switch our model yards just like the prototype does and our steam locos will be able to pull realistic lenght trains.   

[Yampa Bob]

Now I'll drink to that.  I've been watching my DVD again, I'm guessing that from the time the moving locomotive uncoupled from the caboose and cleared the through tracks, the caboose traveled about 6 car lengths before coupling to the other cars.

For, say a 36 foot caboose, that's 216 feet, longer than I previously estimated. Applying the HO scale factor, that equates to 2.5 feet of coasting. For my small layout that would be a noticeable improvement, since my longest ladder track is about 3 feet. 

The procedure was text book perfect, as the caboose barely coupled without  a jar to the other cars. I can't guess the speed at the moment of uncoupling, possibly a few miles per hour.

The switching of the turnout also was precisely timed, as the caboose barely cleared the nose of the locomotive. Of course the angle of the camera might have visually foreshortened the distance.

So....how can we achieve a goal of 100 to 200 scale yards of coasting?  As an experiment, I polished the axle points and journals on one car, it did make a slight improvement.

[Rashputin]

     Just as the comment that a Mike could pull 100 cars is true on level track, once you start adding grades on par with what model railroads use you end up with things like B&O using three EM-1s on a 75 car drag or DRG&W using two L-131 type 2-8-8-2s on 58 cars.  In the case of the EM-1s the minimum speed got down to around ten miles an hour and in the case of the L-131s two engines were used so that speed could be held above 25 mph throughout the run.

     Given the fact that both curves and grades increase resistance (and sharp curves are speed limited as well), most layouts should be looking at what heavy power they need to pull twenty or thirty cars rather than worrying about getting their average single engine to pull more than ten or twelve cars and possibly 15 or so with some of the more powerful modern engines.
 
     When I had a fairly large layout I had a scale for engines such that when a train came in with a Mike but needed greater speed on the next leg of its journey it would have a Mohawk replace the Mike.  When several trains were combined, an even larger engine would replace the others.  I'm not afraid to weight an engine when I need to, shoot, I have a couple of brass articulateds that weight in at 4 1/2 pounds each.  That's enough weight with the motors they have to combine three other trains for the next leg of the route and fit into the scale car limits very well.  It's also enough weight to pull 120 hoppers with various flavors of trucks in a test run on someone else's layout.   Do my Connies or Mikes need to do that even on straight and level track?  Not unless I want it to look like the RR management is stupid for buying the larger engines.  When it comes to diesels, the dynamic brakes sold them to RR management as much as anything else and it takes several engines to hold the train back with dynamic braking and limit the brake applications.  The savings in brake shoes must be incredible if you think about it and if it takes an extra engine to go up the grade, it probably takes at least that much to hold the train back going down it.

    JMHO, but unless you're planning a layout with no grades and twelve to fifteen foot radius curves you shouldn't be pulling much more than a ten or twelve cars without using multiple diesels, something made extremely easy using DCC consisting.

[Jim Banner]

Even fewer problems if your layout is all straight track and down hill both ways.

Seriously, part of the fun of operating a model railroad is having to add another unit or two in some divisions to get the tonnage over the hump.  I even have a couple of pushers on standby for those embarrassing times when I under estimate power requirements.  On their front ends, these pushers have KDs that are glued open.  They can push against a regular KD but do not grab on to it.

[Yampa Bob]

I know that with my small layout, I'm missing out on the fun and challenges of mountain railroading.  All I can do is double up on the locos for a bit of realism, then slow down and pretend they are pulling a grade.  Then when I get over the hump, gradually throttle up and get up speed for the next time around.