Wondering if these US hobbies steam locomotives need to go on a diet?

Nice job on the swap!….how much ballast weight you need will be determined on the job you need the locomotive to do,….remember, this isn’t 3 rail land with great big fat tires, fat rail head, and traction tires,…..now you have a much more prototypical tire contact, and rail head surface for contact……the only way to combat traction issues is with weight…..so if you plan on short trains, sure, ditch the weight, or add a smaller weight, but if prototypical drags are in your future, don’t be so quick to pitch the big honkin’ weights….

Pat

Can you explain why you think there's a correlation between motor efficiency and tractive effort? I just don't see it.

I pull all the weights out.  It is a thing left over from the olden days - heavier was better.

If Im thinking right, thinner steal tyres, and thiner rails could actually increase traction, more ounces per square inch, wider wheels and rail, less ounces per square inch? just, thinking!   I like to put rare earth magnets in those old motors and some ball bearings, then they really pull.       cTr....( Choose the Right )

@Stephen Bloy posted:

If Im thinking right, thinner steal tyres, and thiner rails could actually increase traction, more ounces per square inch, wider wheels and rail, less ounces per square inch? just, thinking!   I like to put rare earth magnets in those old motors and some ball bearings, then they really pull.       cTr....( Choose the Right )

I like your mathematical approach.  Interesting recommendations for the use of those old motors.

All,

Thank you for the interesting responses.  It is appreciated.

Rob

If you want to pull nice long prototypical trains, leave the lead weights IN the model.  If your just pulling short freights or displaying the engines, then thats up to you.  There is a reason the weight is IN there, so the model will pull nice long trains.  Take it out and see what happens, not gonna pull those long and heavy trains.  Replacing the motor just helps get the Amp draw down to something much lower over those old open frame motors, as well as running quieter. 

The oversize weights were left over from the days before free rolling trucks. I remove them.

if you have any sort of grades on your layout, the weight will help get up the hill. we have 2½+% grades at our club layout and weight prevents slipping. that and careful driving.

Some of the MG and USH locos are very heavy, probably too heavy.    I have reduced the size of the weight in a couple.

On the other hand, I don't think you just take the weight out.    A steam locomotive, and a diesel for that matter, has to have the weight somewhat evenly distributed over all the drivers.    The motor is a heavy piece of hardware and sits in the rear mostly over the last set of drivers.     If you take the cast weight out, a lot of the locos weight sits on the last axle and the nose is too light.    this causes a major loss of tractive effort, and a lot of potential for derailments with the lead truck and drivers.   

If you want to take out some weight, I think you need to leave enough weight in to balance the motor.    The farther forward you put the weight, to some extent, the less you need.    If you take a half inch dowel rod, and put it cross ways between the 2nd and third axles on a 4-8-4 for example, the loco should sort of balance.   It won't be exact, but it should not be obviously heavy in either direction.     Balancing the weight across all the drivers gives  you better tractive effort and tracking.

On a separate note, I agree that the MG motors are slow and I have replaced most.   However, I have not replaced motors in most of my USHobbies models.     I lube them a little and run them and they run fine.    I am assembling a painting a 2-10-0 that was "new in the box" that I picked up a few years ago.    It is runs very smoothly and well.    I am not going to mess with a good running mechanism and motor.     I use DCC and I have no problems with using these USH motors.     My decoder of choice is generally the NCE D408SR.     The control is good and smooth.   

Prrjim, I agree the open frame motors in US Hobbies when new or near new are quiet and seem to work well.  What lube do you use on the open frame motors?

I also agree with the weight distribution opinion.  Looks like I will be sawing some weights in half or more.

Thank you,

Rob

prrjim,

When using the NCE D408sr, how do you add sound or don't you?

Thanks,

Ed

@prrjim posted:

Some of the MG and USH locos are very heavy, probably too heavy.    I have reduced the size of the weight in a couple.

On the other hand, I don't think you just take the weight out.    A steam locomotive, and a diesel for that matter, has to have the weight somewhat evenly distributed over all the drivers.    The motor is a heavy piece of hardware and sits in the rear mostly over the last set of drivers.     If you take the cast weight out, a lot of the locos weight sits on the last axle and the nose is too light.    this causes a major loss of tractive effort, and a lot of potential for derailments with the lead truck and drivers.  

If you want to take out some weight, I think you need to leave enough weight in to balance the motor.    The farther forward you put the weight, to some extent, the less you need.    If you take a half inch dowel rod, and put it cross ways between the 2nd and third axles on a 4-8-4 for example, the loco should sort of balance.   It won't be exact, but it should not be obviously heavy in either direction.     Balancing the weight across all the drivers gives  you better tractive effort and tracking.

On a separate note, I agree that the MG motors are slow and I have replaced most.   However, I have not replaced motors in most of my USHobbies models.     I lube them a little and run them and they run fine.    I am assembling a painting a 2-10-0 that was "new in the box" that I picked up a few years ago.    It is runs very smoothly and well.    I am not going to mess with a good running mechanism and motor.     I use DCC and I have no problems with using these USH motors.     My decoder of choice is generally the NCE D408SR.     The control is good and smooth.  

I’d agree with this, beings most 2 rail have full suspension systems, where the weight is, will be just as important as how much,….all of the suspension springs should be evenly loaded,….

Pat

I had thought it was important for traction that all drivers have equal weight.  I don’t “run” trains, but I test them after I build them.  Turns out there really isn’t significant difference sprung vs. unsprung for tractive effort, at least on my undulating test loops.

Seems when a driver leaves the rails the weight is transferred to another driver.

Here is what I have found important:  smooth plated drivers will slip badly until the plating flakes off the tread.  Steel tires are better.

Cast iron is the best by a huge margin.  One side of most older O Scale steam is Meehanite iron, and that stuff has tiny knuckles that grab!

My insulated tires are usually from iron pipe, as found in plumbing supply stores.  Easily machined, not fragile, and yes, grabby.

For me, the biggest surprise was the pulling power of my 84” cast-iron-drivered unsprung Atlantics. They out-pull my fully sprung and equalized CLW Northern with steel tires.

Bob2,

Thank you.  Your experience is very helpful for those of us on the verge of scratch building.  Really interesting about the pulling power of the Atlantic.

Rob

I use Labelle 108 oil as the primary lubricant for motor bearings and axles bearings.    On the old motor, I usually a small drop on each shaft (each end) at the bearing joint.   Many of these motors also have a felt washer in metal "cup" around the oilite bearing on each end.   The metal cup usually has a small hole in the top side as installed.    That felt is an oil reservoir.    I usually put quite a few drops on those if it has one.  

I also put a small drop on the drive shaft on each side of the gearbox, and on each axle at the bearing.  

And of course check the gearbox.   If the grease is still good use it.   If not remove it and put in new grease.    There is also a labelle grease product that I use.

Just because I have photos ready, here are the Atlantics.  17/64 scale, drivers were rough iron castings.  On the Rio Yaqui model, the drivers were modified - all I had was heavy counterweight, and no prototype with this size driver ever had such big counterweights.  Both pull like crazy, with simple NWSL 0.5 Mod gears and Pittman 8000 series motors.

...and neither appear to have tender drive. I guess that's an advantage of 17/64"(?)

Mark in Oregon

I have a Max Grey (MG) PRR 4-4-0 model of 1223.   It does not have a tender drive either.

Someone asked about sound with NCE D408SR decoders,     When I first started converting to DCC, there were not any sound decoders I was aware of that had the capacity to handle O scale - ie 2-4 amps continuous.     The NCE D408SR did have the capacity - 4 amps continuous and latest versions 10 amps stall.    So that became my decoder of choice for most of the steam fleet.     Now there are decoders from Soundtraxx in there 4400 series that are rated to have the capacity.    I think there may be some others.    There is a big cost difference between the sound decoders and non-sound in whatever scale you model.

I finally got around to doing some sound when some friends gave me various decoders they did not like.   These are low amp HO aimed decoders.    I have used a number of these for sound only as a second decoder in steam and diesel locos.     They are generally small and easy to fit in.    The decoder has to have a load to be able to program it I have been told.   And it was recommended by and HO buddy to connect a 100 ohm 1/8 or 1/4 watt resistor to the motor output connections on the decoder.    Then it accepts programming fine.   You do have to run pickup wires to both decoders.    I have about 4-5 steamers done this way. 

I have also found some sound-only decoders from Digitrax and MRC.    These work and have a menu of different soudns - a few different loco types.    I think the digitrax one has 6 different diesel prime movers and 2 steam sound sets.     These are older and some people do not find the sounds as likable as new ones.   

I have  tested the Soundtraxx 4400 decoders, but both installattinos were "newer" models not USH.   One was a Sunset 2-8-8-2 and the other a set of OMI baldwin Sharks.    Both ran well in tests.    The steamer was too big to fit around my scenery and signals, so it was not run far but sounded good and all.   I used the sharks in 1-2 op sessions and there were fine.

I only do tender drive on models with narrow fireboxes.  That way I avoid complicated mounts like that crazy PSC Harriman ten-wheeler.  Just as much room in an Atlantic firebox as there is in a Mountain firebox, give or take a quarter inch or so in length.

One of my personal main considerations is not having visible drive train components.  USH/MG flunk in this regard.  I have converted a MG Daylight to hidden drive train.  I see no use ever for idler gear gearboxes, for that reason among others.

@bob2 posted:

I only do tender drive on models with narrow fireboxes.  That way I avoid complicated mounts like that crazy PSC Harriman ten-wheeler.  Just as much room in an Atlantic firebox as there is in a Mountain firebox, give or take a quarter inch or so in length.

One of my personal main considerations is not having visible drive train components. 

Interesting. One would think the All Nation/Varney Ten Wheeler would have a similar size firebox(?) yet the motor fills up the entire cab: I can see none of that type of stuff in your Atlantics...👍

Mark in Oregon

No - that is a narrow firebox.  Only a very few ten-wheelers had wide fireboxes.

Prrjim,

Thank you for the info for the care and feeding of open frame motors in US Hobbies locos.  

Bob2,

Thank you for more info on your Atlantics.  They are indeed beautiful to my eye.  The lines on the Atlantic type locomotive are under appreciated IMO.

Rob