Tractive power of o scale locomotives

Traction tires are standard on modern 3-rail locomotives. Generally not on 2-rail O scale. Are your engines skidding at startup, on straight tracks or curved tracks? What radius? Do you have just one engine or coupled engines. If so, are the motors on each unit running and turning the wheels or is one unit skidding? If both locomotives are running, remove all the cars and see if the engines run properly without cars. If so, add cars - one at a time and determine how many can be pulled. Pictures and description of your units would help.

MELGAR

Not sure I've ever seen traction tires on 2-rail, they're certainly very rare if at all available.

This subject often comes up.

When I was heavily into N scale, it was generally accepted to change out the TT-equipped wheel sets, mainly to improve the electrical "foot print". They seemed capable of still hauling trains. And if they didn't, we'd just tack on another unit or two. That "foot print" issue doesn't seem to figure so much with these bigger scales...

In O, I think that die-cast steamers, which are pretty heavy, don't really need those traction tires to be able to pull adequately...all of my diesels, which don't have TTs  and are plastic (!), also do okay in the pulling department. None of which addresses the OP's observation...

Mark in Oregon

There are multiple factors in play here:

1. How sharp are the curves involved, how many, and how is the train snaking through them?
2. How many driven axles are pulling?
3. Is there a grade involved?
4. Are the freight cars plastic, brass or die cast?
5. Weight of the locomotives.

My personal experience with MTH locomotives (scale wheels/no traction tires and 3-rail pickup rollers installed) has been mostly with plastic rolling stock and I've been able to pull 20-car trains with a pair of Geeps. I don't recall if the Atlas stack cars are plastic or die cast, but I've pulled trains with six Atlas 89-foot die cast flats with trailers, plus several plastic cars in the mix with a pair of scale-wheeled C44-9W's on point without a problem (48" radius curves/1.5% grades). The operation was on Gargraves and Atlas 3-rail track with Ross turnouts. My testing with 2-rail track was consistent with the 3-rail experience.

You could ballast the engines with a bit of extra weight, but that will potentially tax the electronics controlling the drivetrain.

I have never seen personally an O Scale 2 rail loco with traction tires.

Most of my locos will pull 15 cars on level track  - including a Sunset 44 tonner!    it does depend on the how well the cars roll, and to some extent on weight.    However free rolling trucks make a big difference.     I have a little Sunset H6 (tiny 2-8-0) that will pull 20 cars on level track.

I don't own any Overland stuff and can't comment much on them.    I have been testing a pair of my Buddy's Overland Baldwin sharks, and they pull 20-25 cars on a 1 1/2 % grade.     Both units are powered.

I also have a train of 18 Atlas O hoppers that I pull with a pair Baldwin sharks that have Weaver Mechansims - single motor etc.    These are old LWS alum castings and not terribly heavy but not lightweight.    They will pull that train up a 4% grade on my branch.

Then, to the other extreme, I have an old AHM/Rivarossi FB Morse with a tiny, 3 pole truck-mounted motor that will barely pull itself! 😄

Mark in Oregon

I agree - traction tires are not for scale models.  A lot of brass imports use plated wheels, and they slip like crazy.  The reason they are plated is that long salty trip in a container ship.

If they are steel plated, once the plating wears off you will have decent traction.  If they are non-ferrous, you will have problems with traction and dirt forever.

I machine steam drivers out of iron.  Iron seems to have tiny fingers that reach out and grab the rail - even slippery nickel silver rail with clipper oil on it.

I have spent the better part of the past 30 years trying to find the "sweet spot" between weighting car bodies and optimum tractive effort on older O scale locomotives. I now tend to de-weight older models in favor of cleaning up the drives, wheels etc. and using some common sense about what kind/# of cars they're hauling etc.

Apropos to both Bob and Marks last posts-  I de-weighted (minus 2 lbs lead) an old GMC/AN w/straight cut gears-NW2 and using a replacement drive for the original sintered wheel-set it now will haul 20 heavy vintage (metal, non-needle axle) cars no sweat over grades.

Conversely I have a pair of stock, albeit dual motored AHM C-Liners (jumpered AA's) that only pull 8 tops of the old heavy freight cars, but around 20 to 25 Roco, AHM or USA Weavers with Delrins.

Obviously I have to go one route here or the other with my roster if I wanted to standardize my "operation" on my layout, and the AHM ho motors don't work with either my home layout or my club's profile. My experience with OMI drives has been awful, and they usually require an entire replacement of the towers, trucks and wheels if I want to operate them with brass or older cars.  My biggest issue outside of their drives is the brass trucks busting or bending over the course of normal operation.  

Pulling power has incredible variation…..why only 115…lol

I've worked on more than a few Overland models.  To state their drives are great, good, fair, poor, or terrible wouldn't be accurate.  From my experience they are all over the place.  Early drives were far inferior to the latter.

If you want them to pull more there are numerous things you can try.  Adding some weight (operative word being some) can help.

To say the newer non brass models can out pull a brass model is not factually accurate.  I have built models that can pull very long trains.  Never generalize.

Jay

Overland diesel engines especially the early ones, are extremely poor runners and awful pullers. Quite often, they can barely pull themselves....

As Jay mentioned, most will need to be reworked or upgraded for proper operations.

Micro-Mark sells a little device that can help you measure the tractive power of your trains. I use it regularly on all my restoration and locomotive improvements.

Yves

Sorry, not on topic.

I have to ask.

John, how long did it take you to set up that string of 115 cars?

Jerry

No traction tires here and 200 feet of train

https://youtu.be/-ikBrHi5gvY

Hi O scaler,

thank you for your reply.

Bob2 reply about the plated wheels is very interesting.

If you view it from the physical side you have 2 parameter to get more force on the rail:

1. More weight of the locomotive without overloading the drive motor.

2. More friction between wheel and rail also without overloading the drive motor.

Will make some tests.

Regards,

UPMartin

@UPMartin posted:

Does anyone have experience with the tractive power of Overland Models diesel engines?

Maybe revealing which Overland Models diesel engines are involved may let some of those folks here with real experience give you more specific advice.

For those of you who are Digital Subscribers, you might find this video interesting.

Jim Barrett Tests the Pulling Power of Various 3-Rail Locomotives.

If you are not a Digital Subscriber, but would like to get a Digital Subscription so you can watch this video (and about 50 more!)  CLICK HERE.

This is the 2R Forum.  Why are we seeing all this 3R.  I say keep it where it belongs.

Jay

Sometimes a weak puller can be fixed by balancing it.  More weight usually helps too.  

I had a HO Mikado that couldn’t pull itself out of bed let alone a string of cars up a grade.  After reading about it on some forum years ago I weakened the springs on the leading and trailing trucks and then got lead sheeting and put it anywhere I could find space.  I focused on the front of the boiler and smoke box though since thats where it was lightest.

After that it could hold its own.  

@clem k posted:

No traction tires here and 200 feet of train

https://youtu.be/-ikBrHi5gvY

Wow Clem! That's really impressive. Scale-wheeled locomotives?

I had a Baldwin Model Locomotive Works New Haven EP-3 with two DC-95B motors, each driving one axle with chains to the other two axles; one motor per truck (2-C+C-2). It would pull twenty passenger and head-end cars of mixed brands, construction, trucks, etc. The physical weight of the train was around fifty pounds or so. The EP-3 had no problem with that train.

@Jay C posted:

This is the 2R Forum.  Why are we seeing all this 3R.  I say keep it where it belongs.

Jay

Amen!

Simon

@UPMartin posted:

Hi O scaler,

I'm new in O scale and have the following question:

.... In smaller scales most of the locomotives does have traction tires and can pull long strings of cars. Is this also common in O scale?

Regards,

UPMartin

Excuse me??!! "Most" HO & N Scale locos have traction tyres????? As far as I'm aware the vast majority haven't had them in decades - especially American outline models. Back in the 1980s British model locos had traction tyres and single-truck 'pancake' motors. One of the attractions to many of us was American all-axle drive with flywheel-fitted can motors and the complete abscence of traction tyres!! They were lightyears ahead of British drives and at the time cost a lot less. Kadee couplers was the other major improvement over the standard UK OO 'Tension lock' coupler. It was only from around 2000 that UK manufacturers caught on to the American drive system.

Two-rail O scale locos don't have traction tyres - which are also notorious, along with plastic wheels, for spreading dirt and crud along the rails. Traction is going to be affected by curve radius and weight of rolling stock. The curves on my layout are 36" radius, and a single Atlas Geep or SD will pull about 10 Atlas & MTH cars before slipping. Weaver cars are much lighter so more can be pulled. Lashing up locos would improve things except that I find DCC speed matching locos with different drives & decoders a Dark Art that I have been unable to master.

Yes Matt... scale wheels and high flange wheels, MTH diesel scale wheels are made out of softer metal so they grip pretty good.

Clem an amazing demonstration!

I appreciate you sharing we all can learn from you!

Mark Riggle

@Jay C posted:

This is the 2R Forum.  Why are we seeing all this 3R.  I say keep it where it belongs.

Jay

While I would normally agree, the issue of tractive capability impacts everyone, including those of us who run scale-wheeled locomotives on 3-rail flat-top track. The solutions we find are applicable to both sides of the center rail. Almost all of my MTH diesel purchases since 2009 have been the scale-wheeled versions and over the past decade plus, and I've gained quite a bit of experience with regard to pulling capability, curve compatibility, and track issues.

@SundayShunter posted:

Excuse me??!! "Most" HO & N Scale locos have traction tyres????? As far as I'm aware the vast majority haven't had them in decades - especially American outline models. Back in the 1980s British model locos had traction tyres and single-truck 'pancake' motors. One of the attractions to many of us was American all-axle drive with flywheel-fitted can motors and the complete abscence of traction tyres!! They were lightyears ahead of British drives and at the time cost a lot less. Kadee couplers was the other major improvement over the standard UK OO 'Tension lock' coupler. It was only from around 2000 that UK manufacturers caught on to the American drive system.

Two-rail O scale locos don't have traction tyres - which are also notorious, along with plastic wheels, for spreading dirt and crud along the rails. Traction is going to be affected by curve radius and weight of rolling stock. The curves on my layout are 36" radius, and a single Atlas Geep or SD will pull about 10 Atlas & MTH cars before slipping. Weaver cars are much lighter so more can be pulled. Lashing up locos would improve things except that I find DCC speed matching locos with different drives & decoders a Dark Art that I have been unable to master.

I noticed that the OP is in Germany and the few HO models of modern European / British locomotives, imported by Mehano and Roco, that I owned, all had traction tires.

These are just my opinion,

Naveen Rajan

Matt- he was Kidding!  None of us care when stuff is posted in the wrong place - two railers are just not all that rigid.