EMD said he designed a 3 single axle bogie switcher. What was the horsepower of this switcher? Gary
That was me. It was to be similar to an SW1500 at 1500 HP traction on 3 motors, no different than a 2000 HP GP38-2 with 4 motors. It never got off the drawing board as the cost was still too high to interest the customer. Can't really say for sure the truck I was proposing would work, only some concept layouts were made.
Dave
Well, there's always a switcher ON an EMD C Truck, the TP56. Has three D77s but the Cat C9 (ACERT-37 when introduced in 2016) only makes 375hp. Don't know if that means FA is good or not...
http://www.tractivepowercorp.com/wp-content/uploads/2016/09/Article-2016LocomotiveAnnual_.pdf
Overmod Well, there's always a switcher ON an EMD C Truck, the TP56. Has three D77s but the Cat C9 (ACERT-37 when introduced in 2016) only makes 375hp. Don't know if that means FA is good or not... http://www.tractivepowercorp.com/wp-content/uploads/2016/09/Article-2016LocomotiveAnnual_.pdf
Why does that switch engine remind me of the HO-scale kit in the Walthers Catalog names "The Piker" https://www.walthers.com/21-heavyweight-quot-oscar-quot-quot-piker-quot-set-ready-to-run-pullman
The definition of "piker" I am most familiar with is someone whose financial aspirations exceed their net worth https://thereformedbroker.com/2009/01/24/what-is-a-piker/
I guess the purpose of the Walthers model was to offer a passenger car model kit on a budget for a person starting out and wanting to develop their skills by building a truncated passenger car. The story behind the fictitious prototype is that of a railroad tycoon who doesn't have enough scratch to purchase a full-length private railroad passenger car? One can also suppose that the name is a pun on the pretentious term "pike" used to describe someone's burgeoning model-railroad empire?
There is something equally goofy about that apparently prototypical locomotive riding on a single three-axle truck.
As to the original EMD proposal that went nowhere because its prospective customers were pikers, was that supposed to ride on the EMD guided-axle truck so it would track better than that goofy locomotive someone cobbled together?
If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?
Paul MilenkovicThe definition of "piker" I am most familiar with is someone whose financial aspirations exceed their net worth
The story behind the fictitious prototype is that of a railroad tycoon who doesn't have enough scratch to purchase a full-length private railroad passenger car?
The EMD proposal was considerably grander (call it 3/4 of an MP15, that is not small horsepower!) and the three axle layout might allow essentially zero rigid wheelbase for poor yard or lead track. I hope Mr. Goding provides us with a full technical rundown on what was proposed, because I have never seen it but would surely like to...
The TP56 seems to be aimed for plants that need a small switcher a bit larger than a car mover and less expensive than a Plymouth or Brookville product.
bogie_engineerIt was to be similar to an SW1500 at 1500 HP traction on 3 motors
Think the three motors would have been connected constant series or constant parallel?
Imagine a single axle truck made by cutting the closed end of an HT-C frame about midway between axles 2 and 3 (ignoring the transom), attaching it to the carbody thru rubber compression springs tall enough to allow shear displacement with a tractive connection thru a pair of traction rods at axle centerline height, angled on the end trucks to focus near the loco center, and parallel on the middle truck to allow lateral motion. Most likely have to increase the primary spring travel to compensate for really bad yard track and a lot of modeling to get the focal points and secondary stiffness optimized along with damping. Limited to 60 mph max. Fuel tank to be worked out along with many more details. Per EMD practice at the time, full parallel with an alternator good for 5000 amps with SuperSeries adhesion control.
In the end, too many good switchers out there to rebuild so not cost-competitive, especially factoring in the development cost, which had to be covered by the first order. IIRC, the target sell was to be less than $800K when an SW1500 was approaching $1M.
bogie_engineerImagine a single axle truck made by cutting the closed end of an HT-C frame about midway between axles 2 and 3 (ignoring the transom), attaching it to the carbody thru rubber compression springs tall enough to allow shear displacement with a tractive connection thru a pair of traction rods at axle centerline height, angled on the end trucks to focus near the loco center, and parallel on the middle truck to allow lateral motion.
timzThink the three motors would have been connected constant series or constant parallel?
Overmod Constant parallel, no kludges in load regulation for transition, multiple stages of field weakening used on the motors instead.
Constant parallel, no kludges in load regulation for transition, multiple stages of field weakening used on the motors instead.
No field weakening required, the alternators are good for 1500 V. so can make full speed with no field change.
Overmod What I'm picturing here is more like Klien-Lindner or 'radiating axle' rods, joining at the centerline of the truck with a ball joint of some kind that connects at the right height to the center section, and the parallel traction rods taking the whole thrust from the motored truck (again somewhere near zero weight transfer 'height') to the locomotive frame -- the outer trucks perhaps controlled by composite shear springs arranged to limit their rotation but acting in a 'radial' sense? Or would the composite springs between truck frames do that fully effectively?
What I'm picturing here is more like Klien-Lindner or 'radiating axle' rods, joining at the centerline of the truck with a ball joint of some kind that connects at the right height to the center section, and the parallel traction rods taking the whole thrust from the motored truck (again somewhere near zero weight transfer 'height') to the locomotive frame -- the outer trucks perhaps controlled by composite shear springs arranged to limit their rotation but acting in a 'radial' sense? Or would the composite springs between truck frames do that fully effectively?
The concept was to have three identical individual trucks. The connection point for the traction rods was laterally at the journal centerline and at axle height close to the pedestal on the motor side of the axle running to fixed mounts suspended below the underframe. At the middle truck, the traction rods would have been parallel, at the end trucks the underframe mounts would be moved inward toward the loco centerline so the resulting instant center would determine the effective truck pivot point. Where that optimally is was TBD. We also needed to examine inclination of the rods re weight shift. The rubber compression springs would be soft in shear so the truck can rotate or move laterally without too much yaw stiffness. We never did any analysis to figure the best arrangement out, once the cost was estimated, it was dead.
bogie_engineer No field weakening required, the alternators are good for 1500 V. so can make full speed with no field change.
You mean the D77's were good for 1500V on the terminals? Sounds like a bit of care with insulation would be able to allow two of these in series to run on 3,000V.
Hmmm...
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