GP 9 vs GP 20

3958 views
19 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    January, 2006
  • From: Florida
  • 2,021 posts
GP 9 vs GP 20
Posted by traindaddy1 on Sunday, November 12, 2006 10:43 AM
I have been looking through a few catalogs and have been comparing some Lionel Traditional diesels. A simple question (and it probably has a no-brainer answer) but I'll ask it anyway. When an engine has dual motors, does it mean that the 'pulling power' is double, that is the number of cars being pulled, or is it that the 'pulling power' is just enhanced?  Also, would anyone know if a Lionel GP20 (single motor) would be able to pull   8-10  earlier heavier post-war traditional cars easily?  As always, many thanks for your input.
  • Member since
    July, 2006
  • From: Pisa, IT
  • 1,474 posts
Posted by RR Redneck on Sunday, November 12, 2006 11:29 AM
Well pardner, that means that it has two motors, now look at it this way. If you put to motors in a ford taurus, it wont matter, cuase it really aint got the weight to pull, do it with a dodge dually and you got some pullin power and weight for good traction. It matters more on the weight than the number of motors. But in simple terms, yes, it will pull more than if it had just one motor.

Lionel collector, stuck in an N scaler's modelling space.

  • Member since
    July, 2006
  • From: Plymouth, MI
  • 1,615 posts
Posted by chuck on Sunday, November 12, 2006 11:36 AM
More motors domean more pulling power but it isn't always linear relationship.  The type of motors (open frame vrs can vrs can with flywheels), the drive train, and the weight distribution all have affects on the pulling power/traction of a given locomotive.  You may want to look for reviews of a particular loco or style to get a handle on its pulling capabilities.
When everything else fails, play dead
  • Member since
    February, 2004
  • From: Rolesville, NC
  • 14,122 posts
Posted by ChiefEagles on Sunday, November 12, 2006 11:48 AM
I have some 70/80's Lionel single motored GP9's and U36B.  I weighted them with led weights and they pull a long line of cars.  Without the weights, spin with a very short line.  If you don't have a speaker in the fuel tank, remove it, put weights in it, remount.  I try to get the weights as low to gravity as possible.  Since I travel to Bass Pro Shops and Cabela's, get fishing weights.  BPS also has flat lead bars to melt for casting your own weights and etc.  I stick them inside with the old type windshield rope sealer.  It is very sticky and will hold tight but not permanent.  I just pinch off a piece, stick to weight and it will stick to anything clean.  In fact, a tiny piece on the end of a screw will hold it to your screw driver blade to put those screws in tight spots.  One "rope" wil last for years.  Will hold pictures to a wall or anything else.     

 God bless TCA 05-58541   Benefactor Member of the NRA,  Member of the American Legion,   Boss Hog of Roseyville Laugh,   KC&D QualifiedCowboy       

              

  • Member since
    July, 2006
  • From: Pisa, IT
  • 1,474 posts
Posted by RR Redneck on Sunday, November 12, 2006 11:58 AM
I used regular metal weights that I canibalized from some old TYCO Ho cars that I had.

Lionel collector, stuck in an N scaler's modelling space.

  • Member since
    November, 2003
  • From: The ROMAN Empire State
  • 2,035 posts
Posted by brianel027 on Sunday, November 12, 2006 12:56 PM

Traindaddy, the big factor here is what kind of motor does the locomotive have and how is it mounted?

Now the locos Chief Eagles is referring to are Lionel MPC era locos with an open frame AC motor that protrudes into the sheet metal locomotive frame. Even without the weight, this loco will have more pulling power than other locos I will mention.

Most lower end Lionel locos (along with the basic K-Line MP-15, Alco FA and S-2) have truck mounted DC can motors made by Mabuchi. These locos also use traction tires on the wheels (as do the Lionel MPC locos I mentioned above). The truck mounted motor attaches to the frame of the locomotive via a single pin with a "C" clip holding it. Other than the guide pin, this pin is the point of contact that drives the locomotive. A single motored diesel (such as the Lionel Conrail U36B from 2000) has exceptionally POOR pulling power and will only pull several modern era cars with fast angle wheels. the same is even more so for the single motored Lionel RS-3's with plastic frames.

On the other hand, a single DC can motor in a steam engine will pull more because the motor is mounted in a frame assembly that the body attaches to. Even my single motored plastic body steam engines will easily out pull any truck mounted single can motored Lionel diesel. Adding weight to these steamers will even increase pulling power more. It doesn't help much for the single motored diesel.

What you can do with these diesels is to remove the motorized truck and add a thin washer on top of the truck assembly over the mounting pin between the truck and the bottom of the loco frame. This will tighten up some of the wobble of the trucks as they are, and will help increase pulling power some along with added weight.

On the other hand, Williams uses a single DC motor in their Center Cab switcher. But it is a horizontally mounted motor that is inside the engine housing and protrudes into the truck where the drive armature makes contact with the truck gears. It is also a larger DC motor and has a flywheel. The single motored Williams Centercab Switcher will also easily outpull any truck mounted single motored diesel from Lionel.

I should note Lionel catalogs have been notoriously inaccurate about these features over the past 5 years. Every single lower end U36B has been cataloged with a single motor. The Conrail one (which was the only Lionel engine I have wanted in years) acutally did come with one motor and thus, was a piece of junk - other than its stellar graphics and paint. Even a couple of Lionel value added dealers told me it was junk... and was selling only because it was the first low end separate sale CR loco Lionel had made in over 25 years (and so far the ONLY one).

The WP and CSX U36B's came with dual motors despite the catalog saying otherwise. The same is true with the plastic framed RS-3's, which are also cataloged with single DC can motors. Yet the Ontario Northland version came with dual motors.... go figure.

As for me, I vowed years ago I would not purchase any new Lionel locomotive until another Conrail U36 is cataloged at the same 2000 list price only with the dual motors it should have had in the first place. I ain't holding my breath though, and it's more likely that Williams could end up making the one Lionel engine that I have been waiting for... only it will say Williams on the box.

brianel, Agent 027

"Praise the Lord. I may not have everything I desire, but the Lord has come through for what I need."

  • Member since
    January, 2006
  • From: Florida
  • 2,021 posts
Posted by traindaddy1 on Sunday, November 12, 2006 1:28 PM
Eric/Chuck/Chief/Brianel:  I am always amazed at the knowledgeable answers I get from the readers of this forum and I really appreciate the time spent giving me your input.  This "older" guy thanks you.
  • Member since
    July, 2006
  • From: Pisa, IT
  • 1,474 posts
Posted by RR Redneck on Sunday, November 12, 2006 2:38 PM

Not bad for a high school sophmore, huh?

Lionel collector, stuck in an N scaler's modelling space.

  • Member since
    December, 2001
  • From: Austin, TX
  • 9,598 posts
Posted by lionelsoni on Sunday, November 12, 2006 3:58 PM

The tractive effort or pulling force of a locomotive is the sum of the tractive efforts of all its wheels.

The tractive effort that a wheelset is capable of is the force pushing it against the track multiplied by the coefficient of adhesion.  If the wheelset has magnetraction, that supplies a substantial part of the total force against the track.

The rest comes from weight.  The weight on a wheelset is proportional to the weight that the truck supports through its center bearing.  The proportion of that weight that each wheelset carries depends on how close the wheelset is to the center bearing, compared to the other wheelset(s) on the truck.  It also depends on the tractive effort being produced at the center bearing, which torques the truck frame and transmits more of the weight to the rear wheelset.  This is why traction tires are often put on the rear wheels.  There are techniques (like traction links) used in prototype locomotives to reduce this weight transfer by effectively lowering the center bearing to the height of the railhead.  I have never seen these on models.

There is in principle a similar weight transfer from front truck to back truck, but it is proportional to the difference in height between the center bearings and the coupler, which is very close to zero in model trains.

The coefficient of adhesion is about 1/4 for prototype steel wheels on steel rail and probably not greatly different for models.  However, for rubber tires it is surely much greater.

It should be clear from all this that, as Chuck noted, determining the tractive effort of a particular design is not a simple matter.

Bob Nelson

  • Member since
    January, 2006
  • From: Florida
  • 2,021 posts
Posted by traindaddy1 on Sunday, November 12, 2006 4:24 PM
Bob: Wow!...For this "older" guy, a real learning process.  Many thanks.
  • Member since
    July, 2006
  • From: Southern NH
  • 231 posts
Posted by trainbrain on Sunday, November 12, 2006 5:02 PM
Look at some Williams engines, too. They have 2 mtrs and can pull many cars easily. A good selection and short $$.
Only by the grace of God go I.
  • Member since
    September, 2003
  • 223 posts
Posted by poppyl on Sunday, November 12, 2006 6:57 PM

If you are interested in "traditional" diesels, I would suggest that you look into the Williams products, particularly the dual motored GP-7 or single motored GP-9.  Their GP-9 is considerably heavier than the Lionel product and its pulling capability is much more stout as well.

Poppyl

  • Member since
    January, 2006
  • From: Florida
  • 2,021 posts
Posted by traindaddy1 on Sunday, November 12, 2006 7:19 PM
Trainbrain/Poppyl: Will do! Thanks.
  • Member since
    December, 2001
  • From: Austin, TX
  • 9,598 posts
Posted by lionelsoni on Monday, November 13, 2006 9:04 AM
Traindaddy1, I'm happy you found it interesting.  As for being "older", I think from your posts that we must be near the same age...;-)

Bob Nelson

  • Member since
    August, 2005
  • From: Florida
  • 409 posts
Posted by otftch on Monday, November 13, 2006 9:22 AM

When I use the lower end (one motor in truck) diesels  I just install a motor truck in place of the dummy truck.This will enable it to pull more with less strain.You can pick up these cheaper diesels at most shows for next to nothing with good power trucks.This also gives me a laot of spare parts.You can easily wire the new motor truck in to your engine just by looking at the way the wires are set up in a dual motor diesel of the same type.I recently converted a set of Rivarrossi FM c-liners with a new frame and lionel RS-3 trucks plus some additional weight.They pull fifteen cars with no effort.Don't let anythnig stop you from what you want to do.

                                                                                                      Ed

"Thou must maintaineth thy airspeed lest the ground reach up and smite thee."
  • Member since
    January, 2006
  • From: Florida
  • 2,021 posts
Posted by traindaddy1 on Monday, November 13, 2006 9:42 AM
Otftch: Thanks.      Bob: Could very well be.........but, definitely a "little boy" at heart!
  • Member since
    January, 2017
  • From: Green, OH
  • 3 posts
Posted by GeoPeg on Saturday, August 05, 2017 7:54 PM

[quote user="otftch"]

When I use the lower end (one motor in truck) diesels  I just install a motor truck in place of the dummy truck.This will enable it to pull more with less strain.You can pick up these cheaper diesels at most shows for next to nothing with good power trucks.This also gives me a laot of spare parts.You can easily wire the new motor truck in to your engine just by looking at the way the wires are set up in a dual motor diesel of the same type.I recently converted a set of Rivarrossi FM c-liners with a new frame and lionel RS-3 trucks plus some additional weight.They pull fifteen cars with no effort.Don't let anythnig stop you from what you want to do.

                                                                                                      Ed

 

Ed, the only thing stopping me from adding a 2nd motor truck to my single motor Williams GP-9 is .... finding a motor truck! They must be uber-reliable, I can't find any on the bay or anywhere else. 

I totally agree with your philosophy, but adding a motor truck in place of a dummy truck takes quite an effort in metal cutting and welding in PW Lionel dieselsSmile

  • Member since
    January, 2010
  • 57 posts
Posted by hielsie on Thursday, August 10, 2017 8:06 PM

Laws of physics. Weight over a single point is the same regardless of distance above point. So if weight above wheels with traction is distributed evenly over traction wheels the height doesn't matter. However the higher (greater distance above traction wheels) of the weight, the greater the torque force to the side as a loco takes a curve , thus "un weighting" the driving truck and causing the engine to "want to" derail. So a weight lower is better, but not for the reason stated.

  • Member since
    December, 2001
  • From: Austin, TX
  • 9,598 posts
Posted by lionelsoni on Friday, August 11, 2017 8:48 PM

When the locomotive goes around a curve, a greater proportion of its weight presses down on the outer rail and less on the inner rail; but the total vertical force and therefore the tractive effort remains the same.  That is, up to the point where all the force is on the outside rail and none on the inside rail.  At that point, the locomotive turns over.

Bob Nelson

  • Member since
    April, 2007
  • From: MICH
  • 7,646 posts
Posted by sir james I on Saturday, August 12, 2017 8:38 AM

Short and to the point.

Yes 2 motors will greatly improve the pulling power of your diesels.

"IT's GOOD TO BE THE KING",by Mel Brooks 

  Charter Member- Tardis Train Crew (TTC)   TCA      Detroit3railers                               Detroit Historical society Glancy Modular trains

SUBSCRIBER & MEMBER LOGIN

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

FREE EMAIL NEWSLETTER

Get the Classic Toy Trains newsletter delivered to your inbox twice a month

Search the Community