Andrew,
Not so sure about this...
BMMECNYCThe NMRA standards say 12V minimum + 2V for DCC so new HO minimum is 14V.
Earlier you cited this...
BMMECNYC The RMS value of NMRA digital signal, measured at the track, shall not exceed by more than 2 volts the voltage specified in standard S9 for the applicable scale. S-9 states 12Volts minimum
The RMS value of NMRA digital signal, measured at the track, shall not exceed by more than 2 volts the voltage specified in standard S9 for the applicable scale.
S-9 states 12Volts minimum
So it's not that 14 volts is the minimum. Rather, 14 v is the maximum and 12 volts is the minimum.
Rich noted that NCE systems are adjustable. Mine is set at 12.5 volts, because I have several locos with Tsu-750, which don't like a lot of extra voltage without getting pretty warm. 12.5 volts keeps them cool. There's no troubles meeting schedule, but our terrain inspires considerable caution in most engineers.
Mike Lehman
Urbana, IL
The NMRA standards say 12V minimum + 2V for DCC so new HO minimum is 14V. There are voltage graphs for different scales showing min and max voltages buried in the DCC standards. I'll find and post a link when get to my computer. Another question that should be asked is would an increase in track voltage also cause a lighting function output voltage increase?
Edit: Its S-9.1C link here: http://www.nmra.org/sites/default/files/standards/sandrp/pdf/s-9.1_electrical_standards_2006.pdf
It would seem that between 14V and 16V should be sufficient for HO scale.
ATLANTIC CENTRAL richhotrain Sheldon, first of all, I am shocked that you got your IM F3 to run at a scale 85 MPH. I can tell you with certainty that the top speed of my IM F3's (all four of them) are nowhere near that speed. Maybe DCC accounts for some of the difference, dunno. Second, it is interesting to me that Athearn would package its F3 models as either passenger or freight, based solely on the paint schemes.While you are probably correct in that Athearn (and IM) does not provide different gear ratios for freight and passenger locos, it is just one more reason to laugh at the notion of prototypicality on model railroad locos. Third, while I do desire to get prototypical speeds with my locos, I universally do with the exception of the four Intermountain models. My other 50+ locos all run at acceptable speeds. I stand by my assertion that Intermountain F3 locos run way too slow. Rich Rich, I am reponding to this seperately again for the benefit of others who my not read my longer reply above: Again, about passenger labeling - in the prototype not all passenger F units were geared faster, but passenger service required steam heat equipment - so the presence of a steam heat boiler is what makes an F unit a passenger loco. Gear ratio was based on regional conditions and type of service. As I have said, eastern roads did not gear passenger F units for 90-100 mph speeds. Walthers has lost a great many Proto customers with their slower gearing on their E units because they do not run well with the older versions - making a drive with two different gear rations would be a marketing disaster. Sheldon
richhotrain Sheldon, first of all, I am shocked that you got your IM F3 to run at a scale 85 MPH. I can tell you with certainty that the top speed of my IM F3's (all four of them) are nowhere near that speed. Maybe DCC accounts for some of the difference, dunno. Second, it is interesting to me that Athearn would package its F3 models as either passenger or freight, based solely on the paint schemes.While you are probably correct in that Athearn (and IM) does not provide different gear ratios for freight and passenger locos, it is just one more reason to laugh at the notion of prototypicality on model railroad locos. Third, while I do desire to get prototypical speeds with my locos, I universally do with the exception of the four Intermountain models. My other 50+ locos all run at acceptable speeds. I stand by my assertion that Intermountain F3 locos run way too slow. Rich
Sheldon, first of all, I am shocked that you got your IM F3 to run at a scale 85 MPH. I can tell you with certainty that the top speed of my IM F3's (all four of them) are nowhere near that speed. Maybe DCC accounts for some of the difference, dunno.
Second, it is interesting to me that Athearn would package its F3 models as either passenger or freight, based solely on the paint schemes.While you are probably correct in that Athearn (and IM) does not provide different gear ratios for freight and passenger locos, it is just one more reason to laugh at the notion of prototypicality on model railroad locos.
Third, while I do desire to get prototypical speeds with my locos, I universally do with the exception of the four Intermountain models. My other 50+ locos all run at acceptable speeds. I stand by my assertion that Intermountain F3 locos run way too slow.
Rich
Rich, I am reponding to this seperately again for the benefit of others who my not read my longer reply above:
Again, about passenger labeling - in the prototype not all passenger F units were geared faster, but passenger service required steam heat equipment - so the presence of a steam heat boiler is what makes an F unit a passenger loco. Gear ratio was based on regional conditions and type of service.
As I have said, eastern roads did not gear passenger F units for 90-100 mph speeds.
Walthers has lost a great many Proto customers with their slower gearing on their E units because they do not run well with the older versions - making a drive with two different gear rations would be a marketing disaster.
Sheldon
There's also another whole "physics doesn't scale"/"how real locos work vs models" thing going on - a freight geared F7B could be MUed with a pair of FP7 A's with passenger gearing if necessary, they were just limited to the freight gearing's top speed. Or vice versa. With the way model locos work with a straight permag DC motor, two locos with different gearing just won't run together (unless the motors are also different to compensate. With DCC you can also compensate for this but you are limited to the speed of the slower unit, and if both are supposed to be 85mph passenger locos and one won't go over 60 at full throttle, well, there you are. Indeed, offering different versions of the same loco with different gearing would be an absolute nightmare. DC or DCC, none would operate together out of the box. Not to mention the logistical nightmare in production - Intermountain has already had a problem with mixing up sound and non sound packaging and that's a fairly common practice to offer the same loco with sound and without. OK, so the prototype 215 was an F3 geared for 65, and 273 was an F3 geared for 85 - yeah, nightmare indeed.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
If they added a constantl lighting similar to P2K locos, there's a several diode drop going to the motor, which then has the light bulbs across it - so you can crack the throttle, enough voltage will be there to light the bulbs but the motor will still not see enough to turn. That also means at full throttle, the motor gets about 2 volts (the way the P2K locos are set up) less than if the motor were simply wired right to the pickups.
Now, seeing as Sheldon's results show a 10mph increase with just a little over a volt extra on the rails.. 13V to the rails with a decoder in the way nets about 10.5 volts to the motor at full throttle after all the diode drops are calculated in. Getting the track voltage up to 15-16 volts gets you 12+ volts to the motor, so that should be nearly 20mph faster.
There's simply no way to make them faster without getting more voltage to the motor, which means more voltage to the rails. Of course everything else will get faster - but you can adjust the ones that run too fast to top out at a realistic speed. This generally hasn;t been an issue with HO scale for a long time now, it still exists a bit in N scale where locos routinely do 200+mph on 12 volts and then you mix in the ones that are much more realistic and don't top 100. Things like the AHM MDT switcher and those AThearn RDCs are 70's and earlier vintage, much after that and only cheap train set stuff went warp speed in HO. Not that all old HO was fast - the Flyer industrial switcher I had would do maybe 20 at full throttle.
Doughless richhotrain Sheldon, first of all, I am shocked that you got your IM F3 to run at a scale 85 MPH. I can tell you with certainty that the top speed of my IM F3's (all four of them) are nowhere near that speed. Maybe DCC accounts for some of the difference, dunno. My other 50+ locos all run at acceptable speeds. I stand by my assertion that Intermountain F3 locos run way too slow. Rich Rich, Can you post a picture of the bottom of one of the IM trucks? Maybe yours and Sheldon's are different runs of the F3. I don't know much about IM, but Proto has changed truck designs a few times for different runs of the same locomotive, so the disparity between yours and Sheldon's might be partly due to different/updated truck design and gearing.
richhotrain Sheldon, first of all, I am shocked that you got your IM F3 to run at a scale 85 MPH. I can tell you with certainty that the top speed of my IM F3's (all four of them) are nowhere near that speed. Maybe DCC accounts for some of the difference, dunno. My other 50+ locos all run at acceptable speeds. I stand by my assertion that Intermountain F3 locos run way too slow. Rich
My other 50+ locos all run at acceptable speeds. I stand by my assertion that Intermountain F3 locos run way too slow.
Rich,
Can you post a picture of the bottom of one of the IM trucks? Maybe yours and Sheldon's are different runs of the F3. I don't know much about IM, but Proto has changed truck designs a few times for different runs of the same locomotive, so the disparity between yours and Sheldon's might be partly due to different/updated truck design and gearing.
Intermountain has not changed their gear ratios or the mechanical design of their drive. They have changed the lighting boards, which does account for the speed difference between my older Intermountain F units and newer FP7 units.
As stated previously, this problem is electrical, it is the combined design of the motor, decoder and the lighting board that are different from the other brands in question.
I do believe that the speed differences are caused by the electronics more so than gearing. Electrically you have three things in play inside the loco - the design voltage and speed of the motor, the decoder, and the factory lighting board that the decoder is plugged into.
Those lighting boards even have an effect on DC operation. If I removed them, my locos would run even faster on DC - any/all brands - just ask Dr Wayne who removes all that stuff and runs no headlights.
Obviously these factors each vary from brand to brand, and can vary from one production run to another.
But all this stuff draws off voltage before it gets to the motor, were the motor speed, final voltage and gear ratio come together to provide a specific top speed.
The easiest corrective action to control top speed is to change the input voltage rather than try to redesign the loco.
If I have time, I will also test a set of new Proto F7's I have, I suspect they will be slow as well since Walthers thought it would be a good idea to change their gear ratios - a change many are not happy about.
Again, about passenger vs freight labeling - in the prototype, not all passenger F units were geared faster, but passenger service required steam heat equipment - so the presence of a steam heat boiler is what makes an F unit a passenger loco. Gear ratio was based on regional conditions as well as type of service.
It would be a very bad idea to gear passenger and freight units differently in model form - just like Walthers has lost lots of future E unit customers because their new E units will not run well with their old Proto E units.
In any event, 12-14 volts is considered the normal top range for HO, but that should be 12-14 volts at the motor - not before all the "new fangled electronics".
Again happy to help.
Doughless richhotrain Sheldon, first of all, I am shocked that you got your IM F3 to run at a scale 85 MPH. I can tell you with certainty that the top speed of my IM F3's (all four of them) are nowhere near that speed. Maybe DCC accounts for some of the difference, dunno. My other 50+ locos all run at acceptable speeds. I stand by my assertion that Intermountain F3 locos run way too slow. Rich Can you post a picture of the bottom of one of the IM trucks? Maybe yours and Sheldon's are different runs of the F3. I don't know much about IM, but Proto has changed truck designs a few times for different runs of the same locomotive, so the disparity between yours and Sheldon's might be partly due to different/updated truck design and gearing.
Alton Junction
- Douglas
mobilman44 As an aside, the fastest locos this 71 year old train nut ever had were the Athearn Fs and Gps with the "rubber band drive". For this young teenager, keeping them on the track going thru 18-22 inch curves was a hard task to contend with.
As an aside, the fastest locos this 71 year old train nut ever had were the Athearn Fs and Gps with the "rubber band drive". For this young teenager, keeping them on the track going thru 18-22 inch curves was a hard task to contend with.
But I just cannot seem to get that point across.
Hi again!
I have NOT read all the replies so this may be a repeat............
- Some proto RRs used different paint schemes for passenger/freight operations. Of course the Santa Fe was a prime example. And, those locos were geared appropriately for their designated service. Were there exceptions? I suppose so.
- While I have not tested this first hand, I do know that in every MR loco test where DC and DCC is used on the same loco, there are variances in start speed thru top speed.
For me, I just want my models to have the appropriate speed range for their assignment, be it passenger, freight, local, or switching.
AS AN ASIDE......... the fastest locos this 71 year old train nut ever had were the Athearn Fs and Gps with the "rubber band drive". For this young teenager, keeping them on the track going thru 18-22 inch curves was a hard task to contend with.
ENJOY !
Mobilman44
Living in southeast Texas, formerly modeling the "postwar" Santa Fe and Illinois Central
First, references to "passenger" by Athearn or others regarding EMD F units are refering to paint schemes and/or steam heat equipment which has visably different exterior details at the rear of the roof and elsewhere. Most EMD F units did not have steam heat equipment for passenger service.
Athearn has never offered different gear ratios in their Genesis F units - that would be a marketing problem. Walthers has gotten themselves in trouble by slowing down the gearing of their E and F units compared to the original Proto offerings - many will not buy new Proto E or F units because they are not geared the same as the old ones.
Additional speed tests:
Using an MRC Tech II power pack:
track voltage at full throttle under load - 14.6 to 14.8 volts
Intermountain EMD F3 - 85 smph - up from 75 smph @ 13.2 volts
Genesis EMD F7 - 90 smph - up from 80 smph @ 13.2 volts
old production Proto E8 - 95 smph - up from 83 smph @ 13.2 volts
So a 1.5 volt increase resulted in a 10 smph top speed increase across the board.
Turn your voltage up - get at least 14 volts to the motor, after the decoder circuits, you will get the speeds you desire.
Other points - I don't know how mid western roads had their F units geared. I'm sure western roads who used them for passenger serivce, like the ATSF, likely had them geared fast. But here in the east, even E units were generally only geared to the 85-90 mh range.
Incidentally, my Athearn Genesis F3A's list "passenger" on the label on the box. So, Athearn does distinguish between passenger and freight locos. Rich
Incidentally, my Athearn Genesis F3A's list "passenger" on the label on the box. So, Athearn does distinguish between passenger and freight locos.
"Passenger" may just be referring to the paint scheme. Many roads had different paint schemes for passenger and freight locos.
richhotrain Sheldon, are you saying that I should increase the voltage to 16 volts? Rich
Sheldon, are you saying that I should increase the voltage to 16 volts?
That is what I would do. I bet at 16 volts those Intermountain units run 75 smph.
If I get time tonight, I'm going to run some DC tests at higher voltages with some other power packs I have.
BMMECNYC Sheldon, Here are the specs from the Walthers website. Flat Can Motor 12VDC 16 x 27mm, Double Shaft 1.5mm Dia. x 9.5mm, 12,500rpm (Repl. #122719) Walthers Part # 53-1627D9A scale,$24.95, currently in stock at Walthers Edit: The RMS value of NMRA digital signal, measured at the track, shall not exceed by more than 2 volts the voltage specified in standard S9 for the applicable scale. S-9 states 12Volts minimum From RP-9: Powered equipment shall operate at a speed within 25 percent of their nominal maximum prototype speed divided by the appropriate scale factor (See STANDARD S-1) under the following conditions: The input voltage shall be the minimum voltage stated in Section I A of STANDARD S-9. The unit running "light" after a run in and lubrication according to the manufacturer's instructions, on level, tangent track laid at minimum gage.
Sheldon,
Here are the specs from the Walthers website.
Flat Can Motor 12VDC 16 x 27mm, Double Shaft 1.5mm Dia. x 9.5mm, 12,500rpm (Repl. #122719) Walthers Part # 53-1627D9A scale,$24.95, currently in stock at Walthers
Edit:
From RP-9:
Powered equipment shall operate at a speed within 25 percent of their nominal maximum prototype speed divided by the appropriate scale factor (See STANDARD S-1) under the following conditions:
The input voltage shall be the minimum voltage stated in Section I A of STANDARD S-9. The unit running "light" after a run in and lubrication according to the manufacturer's instructions, on level, tangent track laid at minimum gage.
Respectfully, that motor is not going to be a drop in replacement. Without knowing for sure the cause of this problem, I would not be cutting up locos to install different motors.
NMRA S-9 was revised at the beginning of the DCC era, it orignally called for reasonable top speeds at 11 volts.
I still believe that 12-13 volts to the motor will produce the desired speed increase - at 13.2 system voltage, the motor is likey only seeing 10-11 volts.
The speed of a replacement motor at 10 volts is subject to testing.....
Randy,
I think the two volts would make the difference......
All my early understanding about DCC in HO was a working track voltage of 15-16 volts.
That should produce a motor voltage of just over 13 volts - then speeds should be similar to my results.
13.5 volts in mean only about 11 volts to the motor......
I never tried to accurately measure them, but I'm pretty sure my Stewart FT and F3's don;t run 80+mph at full throttle.
The thing here is the difference between the IM and Athearn on DCC, which does not appear to exist on DC based on Sheldon's results. Unless IM changed gear ratios in different releases. There's a difference in decoders, but outside of some known things, like Digitrax reserving some of the top end for BEMF speed control to work - which is why disabling BEMF on the Digitrax decoder brought the speed of the two IM units into alignment, there's really no reason for it. The details vary, but all decoders work pretty much the same, there's a bridge rectifier and then an H bridge driven by PWM to control the motor. The pulse amplitude is going to be the track voltage less a few diode drops (in the rectifier and in the drive transistors in the H bridge). So a decoder loco with a DCC track voltage of 13.5 volts will be slower then the same loco with no decoder and running on DC that peaks at 13.5 volts. But here we have the Athearn unit just as fast on DCC as it is on DC. Only the IM units have a problem. As for system differences, Digitrax's larger systems all have a scale switch to set track voltage, the HO setting is about 15 volts, the N scale is about 12 volts (assuming you use a proper power supply). On their starter systems, Zephyr and Zephyr Xtra, they don;t have thise setting and the voltage is fixed at around 13 volts to be suitable for both scales. NCE does similar with the PowerCab, one less setting to worry about for the beginner. Because of the drops in the decoders, this will usually result in a slightly lower top speed than the same loco without a decoder on a standard DC power supply. The slightly higher HO setting on the bigger Digitrax systems compensates for the losses in the decoder so the motor gets to full speed.
More voltage will equal faster speed, but the most you really want with HO is about 15 volts on DCC. For large scale, which often has motors that run on more than 12 volts, it's more like 20-22 volts DCC.
richhotrain I spoke to a technician at Intermountain yesterday about the scale speed issue with my F3 locos. He ruled out the decoder or the motor as the cause. He did agree that turning off BEMF would help a little, but felt that the gear ratio was the source of the "problem". However, he did not feel that the gear ratio was a problem in general, and he indicated that changing out the gears would not be practical or even recommended. Rich
I spoke to a technician at Intermountain yesterday about the scale speed issue with my F3 locos. He ruled out the decoder or the motor as the cause. He did agree that turning off BEMF would help a little, but felt that the gear ratio was the source of the "problem". However, he did not feel that the gear ratio was a problem in general, and he indicated that changing out the gears would not be practical or even recommended.
Did the tech indicate in any way that he knew that the IM locos are designed to run at a slower top speed?
It sounds like IM is not aware of what top speed they designed the loco to run if they can't tell you why it runs slower. Maybe they didn't design-in any particular top speed.
Just speciulating.....Weren't the IM F units originally designed to fit over Stewart chassis? I'm thinking maybe the gear ratio is just left over from parts/design of that chassis...that when they upgrade the electronics and price of the locomotive, they didn't redesign the entire drivetrain but used the same chassis/drivetrains that were being supplied to/by Stewart...which may have been based on frieght loco gearing.
Whereas the locos you are comparing them too were designed fromt he ground up to perform more like the prototype.
ATLANTIC CENTRAL I wonder what voltage the power supplies of other DCC systems are. I remember hearing numbers as high as 16 volts with Digitrax.....I could be wrong. 13.6 seems low considering it is AC and needs to rectified in the decoder. A diode bridge (rectifier) is easily a 2 volt loss......11 volts to the motor, plus losses in the factory lighting board before the decoder, no wonder the locos run slow.
I wonder what voltage the power supplies of other DCC systems are. I remember hearing numbers as high as 16 volts with Digitrax.....I could be wrong. 13.6 seems low considering it is AC and needs to rectified in the decoder. A diode bridge (rectifier) is easily a 2 volt loss......11 volts to the motor, plus losses in the factory lighting board before the decoder, no wonder the locos run slow.
NCE states that the 5 amp system is factory pre-set at 13.8 volts, but it is adjustable.
richhotrain ATLANTIC CENTRAL I'm not a DCC "expert" so I will ask, does track voltage effect maximum output voltage to the motor? I would think so. So Rich, what is your track voltage? Does this vary from brand to brand? is it adjustable in any way? Higher voltage should provide a higher top speed.........at least with DC. My Intermountian locos run 20% faster on DC than what Rich records on DCC - seems like a big drop - and again, I'm using 13.8 volts, 13.2 volts under load. Most DC power packs put out more than my 13.2 volts. As soon as I have time, i'm going to run some tests with several MRC packs I hove on hand - and, I can actually increase my regular power supllies by about one volt - might tes tthat as well. Sheldon I have an NCE Power House Pro 5 amp DCC system. The voltage is steady at 13.6 volts, a reading of 13.2 volts with the loco under load. Randy indicated earlier in this thread that more voltage would not produce more speed in DCC since the motor only draws so much current from the decoder. Rich
ATLANTIC CENTRAL I'm not a DCC "expert" so I will ask, does track voltage effect maximum output voltage to the motor? I would think so. So Rich, what is your track voltage? Does this vary from brand to brand? is it adjustable in any way? Higher voltage should provide a higher top speed.........at least with DC. My Intermountian locos run 20% faster on DC than what Rich records on DCC - seems like a big drop - and again, I'm using 13.8 volts, 13.2 volts under load. Most DC power packs put out more than my 13.2 volts. As soon as I have time, i'm going to run some tests with several MRC packs I hove on hand - and, I can actually increase my regular power supllies by about one volt - might tes tthat as well. Sheldon
I'm not a DCC "expert" so I will ask, does track voltage effect maximum output voltage to the motor? I would think so.
So Rich, what is your track voltage?
Does this vary from brand to brand? is it adjustable in any way?
Higher voltage should provide a higher top speed.........at least with DC.
My Intermountian locos run 20% faster on DC than what Rich records on DCC - seems like a big drop - and again, I'm using 13.8 volts, 13.2 volts under load.
Most DC power packs put out more than my 13.2 volts.
As soon as I have time, i'm going to run some tests with several MRC packs I hove on hand - and, I can actually increase my regular power supllies by about one volt - might tes tthat as well.
I have an NCE Power House Pro 5 amp DCC system. The voltage is steady at 13.6 volts, a reading of 13.2 volts with the loco under load.
Randy indicated earlier in this thread that more voltage would not produce more speed in DCC since the motor only draws so much current from the decoder.
I'm not so sure about that. As long as the working limits of the circuit are not exceeded, more voltage should equal more speed.
Curent is a function of voltage and load, volts x amps = watts, more a function of the motor windings than a function of the decoder - that's why the wrong motor will fry a decoder that cannot handle enough current.....
Again, I'm not a DCC expert, but I will aska few if I get a chance.
BMMECNYC My guess is IM assumes most customers will either run on layouts in a smaller space or run freights with Fs.
My guess is IM assumes most customers will either run on layouts in a smaller space or run freights with Fs.
ATLANTIC CENTRAL The fact that Rich has two different top speeds from two locos that are identical except for the decoders, points in the obvious direction to me - that one variable seem like the likely cause - combined with my question above - what is the working track voltage of the DCC system?
The fact that Rich has two different top speeds from two locos that are identical except for the decoders, points in the obvious direction to me - that one variable seem like the likely cause - combined with my question above - what is the working track voltage of the DCC system?
BMMECNYC Would it be possible to aquire a higher speed motor of similar size? If this was a larger locomotive I would suggest a possible step up gearing (add a large gear on motor shaft, meshing with a small gear on the worm shaft) to give an increase in speed, but I doubt you have space in an IM F unit for that. My guess is IM assumes most customers will either run on layouts in a smaller space or run freights with Fs. And a similar experiance with unsatisfactory top speeds: I was at a hobby shop near Boston, MA a couple years ago and was looking at buying a Bachmann Spectrum J. Fortuneately for me the guy working the HO scale counter (they have separate counters for different scales, have to segregate the 3 rail folks from 2 rail, otherwise you end up with arguments and name calling!) volunteered to run it on their 10ft test track. Time from one end to the other: >20 sec at max throttle setting. He could tell that I was no longer interested in purchasing it and boxed it back up and set it in a cardboard box on the floor behind the counter for shipment back to Bachmann. Edit: NWSL has one that spins at 12,500rpm. Dont know what IM uses. Available on walthers for $25.
Would it be possible to aquire a higher speed motor of similar size? If this was a larger locomotive I would suggest a possible step up gearing (add a large gear on motor shaft, meshing with a small gear on the worm shaft) to give an increase in speed, but I doubt you have space in an IM F unit for that. My guess is IM assumes most customers will either run on layouts in a smaller space or run freights with Fs.
And a similar experiance with unsatisfactory top speeds:
I was at a hobby shop near Boston, MA a couple years ago and was looking at buying a Bachmann Spectrum J. Fortuneately for me the guy working the HO scale counter (they have separate counters for different scales, have to segregate the 3 rail folks from 2 rail, otherwise you end up with arguments and name calling!) volunteered to run it on their 10ft test track. Time from one end to the other: >20 sec at max throttle setting. He could tell that I was no longer interested in purchasing it and boxed it back up and set it in a cardboard box on the floor behind the counter for shipment back to Bachmann.
Edit: NWSL has one that spins at 12,500rpm. Dont know what IM uses. Available on walthers for $25.
Well if he was running a DCC decoder equiped loco on a DC power pack, I'm not surprised - that's just one reason I remove all those pesky decoders.....
The last thing I would do is start hacking up a perfectly good Intermoutain loco with different motors or gears - something else is wrong.......
12,500 RPM at what voltage? We still don't know that info?