For pulling POWER diesel or steam?

I would suggest using a USA Trains F3's AB units. Both are powered units.

http://usatrains.com/usatrainslocof3.html

I have some that the grandkids have ran for many years and still holding up. They have been real work horses.

Dual powered units sound good Livesteam53 but for over $700!! That's too rich for my poor RR. Plus I like the style of the GP series engines, and I like even better that they are not much more than $200. They do have 2 motors but weight and traction are also factors in the pulling power arena. Does a geared Bachmann loco have better power than a 2 motored diesel GP30?

My most impressive pullers are my e8's, although I don't have a SD45.

I remove traction tires, so my USAT diesels don't have much pulling power, I figure mostly because they weigh less... simple physics.

I'm not sure that my non-ball bearing USAT locos will stand a lot more weight, but with the ready availability of USAT wheelsets, I think I will give adding weight a try.

Regards, Greg

The formulae for working out the effective effort of a model locomotive have been around since 1904. Basically for each Kilogramme of weight that is taken by the driving wheels 230 Grammes of that is available for traction, So, in a C0-C0 loco that weighs 5 Kilogrammes, 1.150 Kilogrammes is the maximum tractive effort. While for an A1A-A1A loco, 766 Grammes would be the maximum. Electric traction motors develop their peak torque at far lower rotational speeds than a steam loco using pistons, thus pull better at lower speeds. The P.L.A.N. formula gives the peak power of your steam loco -but this does not really work too well at Gauge 1 and smaller scales... A more accurate formula (or rather less inaccurate!) is to use simple physics and ignore adiabatic and isothermal effects and treat the system as one under constant thrust with no lead and lap effects.

regards

ralph

You missed the coefficient of friction being different for traction tires I think.

With the suspensions on model trains, I don't think we get anywhere near theoretical.

By simple empirical evidence USAT locos pull more with traction tires than without, no other changes.

Regards, Greg

Whoa!

Steam pistons???? Steam outline electric drive.... wrong apples....
If you are comparing 2 motor dismals then perhaps an articulated w/ 2 motor blocks is the model to compare.... ignore the pilot and pony trucks, they don't carry a scale load, if you use Ralph's logic.

John

In this instance, I would say anecdotal evidence is going to be more reliable as an indicator of which brand and type of Large Scale locomotive pulls the most cars.

Dave Goodson has first hand experience of a battery powered R/C controlled early Bachmann Shay hauling 30 + pieces of stock up a 4 % grade. Of course the plating was worn off the wheels which aided adhesion and thus hauling power.

I had an Aristo Craft Pacific that was 17 years old. It can pull a Volkswagen, lol. Gave it to my son, he rebuilt it (he's a marine electrician) and God only knows what it will pull now. It also has a high speed and can handle a 4% grade. This is a link to his site. http://users.eastlink.ca/~brownscountry/index/Home.html

I had an aristocraft Pacific which was an excellent puller. I cut it down to make an Atlantic out of it (4-4-2 instead of 4-6-2) and it pulls better as an Atlantic. The weight is the same, so I can only figure it's because the shorter wheelbase tracks better through curves. The Atlantic is a better puller than my Aristo Rs-3.

I believe in real life that the bigger steam engines,like the northerns, were far better individual pullers than the diesels that replaced them, but the diesels were far better in terms of maintenance costs and ease of consisting--three Rs-3s were cheaper and more effective than one northern

Yes Greg....

I did use the standard figures for steel to steel rather than steel to A.N.OTHER -this is because I cannot define what the coefficient of the frictive medium used for the tyres(!) The suspension does not really affect the tractive effort -but does play a part in how the power curve is delivered to the track. At a constant speed the suspension does not affect the tractive effort -but while the loco is applying power and braking with its motors then "tramping", "rearing" and "shimmy" of the drive wheels to the rails should be absorbed by the suspension and the stored energy returned to the direction of thrust.

UK Railway Terms Glossary:

Axle Tramping = the action of the driven axle gear wheel to force one side of the axle into the rail lowering the load on the wheel at the other end of the axle -sometimes to the point where the wheel will lift off the rail.
Bogie Rearing = the action due to "weight transfer" during load and braking in which the transfer can lower the effective weight on a bogie causing the flanges on the wheel to climb the rail.
Wheel Shimmy = the action of a wheel when changing speed to act as a gyroscope and present a precessional force to the bogie -causing the wheel to lift especially while cornering.

regards

ralph

Weight on drivers times .23, eh? An interesting bit of information to have handy. Perhaps it may vary a bit for brass wheels or plating.

Thanks Ralph.

Actually the coefficient of friction should only be related to kinetic friction, not static friction.

My point, which may not have been obvious (but I knew Ralph already knows) is that with the suspension and bumping around, our locos may be in a state of kinetic friction even when starting out (occasional wheelslip) because of the suspension causing intermittent contact with the rails.

Kinetic friction is lower than static friction.

But just us physics-heads worry about stuff like this.

I'm in the general frame of mind that - as Tony says - the empirical (he said anecdotal, same meaning here) evidence is probably the best to go by.

Regards, Greg

Wow alot of great answers here from some very intelligent people that have actually gone way beyond my original question and my understanding.
I'm not a rocket scientist after all! LOL
But really to rephrase my question removing the real world friction ratios etc... What pulls better right out of the box with no modifiications, is more reliable with less maintenance and less worry about blowing out a gear, a bachmann shay or any of their geared loco offerings, a USAT GP 30 or GP38 2 motor diesel, or an equivalent 4 axle aristocraft diesel style engine?
And if i could add in one other question... which is easier to convert to battery power, a steam or a diesel? I would suspect the diesel.
Thanks for your answers.
Todd

I don't have a 4 axle Aristo with the new prime mover (only the GP-40 is in this class).

I've had poor luck with the other Aristo 4 axle trucks, I think the older (bearings in sideframes, sprung) style were more rugged than the newer style. But I think they pull better than a USAT 4 axle that has no traction tires.

With traction tires, the USAT will pull better, but you might get a split axle. Notwithstanding that, I think the USAT 4 axle trucks are lower maintenance.

The bachmann products all have split gear or other problems, even though the shay is quite a puller.

If I wanted the lowest maintenance best 4 axle puller I would get a GP-40.

Next choice would be an RS-3

If the criteria was only pulling power, a USAT 4 axle with traction tires (but my experience is more maintenance)

It's not as simple as a go no go here. Also, you have mentioned 1:20.3 and 1:29 locos.

On the easiest to convert... Aristo locos with a socket.... take your pick, they are all dead easy.

Regards, Greg

The new Shay trucks are reportedly quite good. I don't have one myself, so I'm left to go on the experiences of others, but from what I'm led to believe, the "new" truck design fixed the issues that plagued the original model. Those who run them have demonstrated them to be very good pullers. (While chasing down a rampant spammer this morning, I came across a post from someone using his Shay to plow snow. If anything's gonna stress your gears, it's that.) I've got a B'mann Heisler, and it's been beautifully reliable for coming on 7 years now. I've never physically tested its pulling power, but it's certainly demonstrated no lack of strength that I've seen. The Climax is a lighter locomotive than either the Shay or Heisler, so I'd be led to believe it's not quite as strong a puller, but not having one to compare, that's just speculation.

In terms of converting to battery power, given the options you're looking at, I'd say the diesels would probably be a bit easier for no other reason than you've got the benefit of the entire hood to play with for room. The Shay's bunker is a bit smaller, and your Tetris skills will come into greater play.

Later,

K

I'm testing my new "Big John" Dunkirk Geared Locomotive by Hartland Locomotive Works, (HLW), made in the USA, warranteed for one year or 800 hours commercial use. It was pulling a heavy sound box car plus 11 tank cars with steel wheels and a caboose up a 2 percent grade all day and evening last Thursday. Iit's kinda ugly but powerful with a motor in each truck and sells for around $300 depending on the deal. It's not a diesel but so far so good.

I would have to second Ron's recommedation, the Hartland "Big John" has got to the most unheralded LS work-horse
ever built, have one here that has about 4,000 hours on it, an it'll still pull the house down...
Paul R...

For converting to battery power the diesel would be easier due to having a bit more room to work on and maybe hold the battery. You could also build a battery car and put it behind the steam loco and then not worry where the battery goes.

Far as the 4 axle diesels I'd go with the AC GP 40 due to not having to deal with USAT traction tires and then worry about gear problem coming loose from the axle if you over tax the unit. Later RJD

While dismals have hoods, Steamers have tenders and empty boilers. In my small 2-8-0 the batteries went in the boiler and the electronics in the tender. To make up the weight I added lead shot where ever I could. She pulls the same as before....

I always put the batteries in the tender.

With Diesel, you don't have rods to worry about. I have steam

For steamers with tenders, absolutely the tender's ideally suited for the electronics. It's the locos without tenders that present the challenges. Not insurmountable by any means--and getting much easier with smaller battery technology--but still requires a bit of additional thinking.

Later,

K

Prototypically? It depends.... A steam locomotive can easily pull a train that it can't start. A diesel, OTOH, can start a train that it can't pull. It's all in the mechanics of how they produce their power.


Most of us worry more about which kind we LIKE more, over which has the most absolute pulling power. If you're needing more 'oomph' you simply do what the real RRs did... you add a second (third, fourth, 6th) unit. I've seen something like a 5 diesel lashup on the head end and 2 pushing in coal drags on Horseshoe curve. With steam you would have had a double or triple header, a mid train helper(or two), and a pusher.... The only limits are your mainline, your wallet, your power supply, and your ingenuity.


If all you are concerned about is pulling stumps, as suggested, look into the HLW Big John.

I looked up the BIG JOHN and you guys are right it is not the best looking engine out there but it looks like muscle and that it could haul a ton but I am more interested in a diesel. From what I am learning here from your answers is that an Aristo GP40 does not have a traction tire like a USAT GP38 uses. So if the USAT hits a bad spot while pulling a heavy load and starts to spin the traction wheels could transfer the energy to the gears and do some damage VS the Aristo that doesn't have traction tires so that one would just sit and spin its wheels. A friend of mine has an Aristo RS3 and he loves it so I know that is a good engine but I like the looks of the GP style.
It would seem that you guys are leaning towards the Aristocraft engine vs the USAT which is interesting. One of my concerns is the Aristo scale of 1:29, I have a mix of LGB and Bachmann engines and their size seems to play well together but will the Aristo diesel look way out of place.
I have enough juice to run 2 or 3 engines on the main at the same time but not lashed together. If one engine is faster than the other wouldn't that put an undue strain on both drivelines?

You want a diesel to go with your 1:20.3 Bachmann and your 1:whatever LGB and 1:29 looks out of place?

I sure hope so! hahahahahaha

Seriously, you should have stated this before... you want a larger scale diesel. Do you want a narrow gauge one? If you are concerned about appearances I would stick to 1:20.3, but you are not going to find a 1:20.3 LARGE diesel with a bunch of pulling power.

No matter what 1:29 you buy, it won't scale "right" next to the other locos.

Yes, speed mismatch can cause problems too.

I think you need to sit down and ponder this a bit more... seems your priorities are not quite hashed out...

scale
pulling power
maintenance
speed compatibility with other locos (which ones)

If you are going to stay with narrow gauge prototypes, or weird scale steam, which is about 1:22 or whatever, you might want a bachmann Davenport, but sounds like you want big muscle and modern.

That is NOT available in narrow gauge at any reasonable price and modern won't look right next to a NG steamer.

Why not just bite the bullet and don't run them next to each other? Get any Aristo or USAT diesel. They will all do fine. If you need more pulling power than one loco, buy another and doublehead. If you are constantly trying to extract the maximum power from a loco, you will probably wear it out prematurely any way.

Regards, Greg

The definitive answer: (okay, I'm being obnoxiously egotisitcal with that statement... but, I bet it got your attention ;-) )

Anyways, my thoughts:

The Bachmann Shay (and Climax and heisler) and the Aristo or USA Geeps (GP's or "General Purpose") are, for all practicality, the same engine. In each case, the locomotive is a solid frame supported by two pivoting, self-contained power assemblies. Those assemblies are all two-axle trucks. Both axles are geared to a single motor through worm and pinion gears.

This means you need to consider the aspects of other issues. Bachmann's trucks have a history of issues, however by most reports they seem to have solved the issues in the later revisions. I have an early edition, which reduces my ability to state facts here. However, one thing to consider... there is now a 3-truck shay available (a premium price though). And prototypically, there were 4-truck shays. This would effectively increase your pulling power. However, there is the maintenance issue.... The shays and other logging engines have metal rods which need periodic lubing, much like the original prototypes. Is this an issue for you?

The USA trucks have the split axle issue. Are you willing to deal with this? The good thing with this engine is the increased tractive effort created by the use of traction tires. However, this is also a bad issue, and might be at the heart to the split axle(though I don't know this to be true)... When overloaded, the traction tyre will prevent slipping. This means the locomotive will stall out. The motor will stop turning, yet the torque created by the magnetic fields in the motor will still be present. This WILL put strain on the gears. If the traction tyre is on one wheel on an axle, and not on the other, it could create uneven torque conditions within the axle. IF you can figure out the limits of the engine and ensure you don't exceed its mechanical limits, the USA traction tyre equipped truck will serve you well. To overcome the reduced power pickup created by the traction tyre, they are equipped with sliders like the LGB products. As traction tyres age, they dry out and become brittle. Eventually they will tear apart and come out, leaving a heavy groove in the surface of the wheel, necessitating the locomotive's removal from service.


The CURRENT Aristo truck is equipped with ball bearings within the drive train. This will allow it to handle a great deal of additional weight to act as ballast to increase its tractive effort. The bad: Aristo's quality control issues are well known, however they always backup their products. If there is an issue, they will work with you to solve it. Aristo has consistently stated that they do no like the sliders' toy-like appearance, and consequently designed a modular ball-bearing equipped gearbox to allow them to skip the traction tyres and use pure adhesive weight for traction. The advantage here is that unlike traction tyres, which adhere to the rail through friction, the steel Aristo wheels adhere to the rail through gravity. When the load being pulled by the engine exceeds the adhesive weight of the engine, the engine will stall. Unlike the USA diesels, the wheels are free to slip on the rail surface. From the time the locomotive stalls until the wheels break free of the rail, there will be increased stress on the gearing.


Once the wheels break free and begin to spin, the stress will be reduced. As long as you don't weigh now the engine with an excessive amount of weight, the traction motor's torque will always exceed the adhesive weight of the engine. There is a down side to a stall with the wheels spinning. Like any metal on metal without lubrication, there will be a tendency for the metal to be destroyed. This will usually end up with depressions ground into the rail... definitely in aluminum rail, most likely in brass. I don't know which is harder... the steel drive wheels or the stainless steel rails. I believe Aristo said the wheels were harder, but I don't know if anyone who has confirmed this. The decision to be made is which is easier to deal with? a locomotive out of service until its traction power systems are repaired, or like the real railroads, cutting out a bad section or rail and replacing it?


Your decision should probably be based on two factors:

1) Do you want steam or diesel?


Steam? then your choice is:
Bachmann: 2-truck shay, heisler, climax or three-truck shay
Hartland's Big John, (which could be bashed to look more like a climax or Hiesler, check the model making forum)

Diesel? Here you have a much wider choice:
Aristocraft: FA-1 & FB-1 (individually or sets), RS-3, GP-40, or the RS-3-based Centercab

Bachmann: You might still be able to find their GE Centercab switcher
USA Trains: GP-7/9, GP-30, GP-38-2, Alco S4, GE 44-ton Centercab, NW-2 (calf&cow sets available)


In both steam and diesel outlines, you could also consider two (or three) doubleheaded little critter engines. Aristo has their little RS-1/3 or their 0-4-0 Steam switcher. Bachmann has a variety of x-4-x based steam engines you could consider. Hartland has their little Macks in both diesel & electric version. USA has their critter based on the NW-2 (an NW-1/2?) but I see its not listed on teh site anymore. There are a host of smaller LGB engines that go on ebay at any given time. Two of these could help as well. If you were to go with teh critter option, I'd highly recommend adding "heavy" wires to make them electrically one engine, basically giving you steam Geep.


Your other question was about mismatched speeds... I've given this a lot of thought lately. If you ever see pictures/video of the NS yard crews working in Enola or Altoona (both PA yards), they are often using a remote controlled GP-38 coupled to an MP15DC, which is the modern equivalent to the old NW-2 or Alco S4. They don't match speeds either.


Here is my thought on the issue: every time we pull a train, we have speed-mismatched equipment: The engine is always faster than a freight car (unless the brakes are released and the car is rolling down hill) Test the engines you want to lash together. if they are fairly close, it shouldn't matter which order you put them in the consist. If you are running a VERY light train, or there is a large speed difference, I'd put the faster one in the front. This is because it be no different than putting a large train behind it that forces it to slow down.

However, I would NOT try to run a shay with a Geep.

Oh, that brings up one thought I wanted to caution you about. The Shay is a good puller because of its gearing. Changing the gearing increases the torque available to the wheels, but reduces its top speed. If you have big hills and kids who like to run at "light speed", this could be a benefit... the shay's gearing will make it impossible for it to go careening out of control and wrecking at the bottom of the grade (or on any curves on the grade). However, it's top speed might be too slow for your preferences. You might want to consider this factor in making your decision. The shay, hiesler and climax all run significantly slower than any other engine on the market.


Good luck on your choice, let us know. I personally am planning on double headed LGB 2-4-0's for the branchline on my railroad while 4-6-2, 2-8-2 and other big steam ply the mainline.