MP steam... pulling the wires?

[daniel_leavitt2000]

I seem to collecting basket case Model Power steam for good prices. This latest one is another pacific.

I took the thing completely apart. And it goes back together without much fuss when I leave all the wheel wipers and wiring off.

Do you think a Bachmann tender would have enough electrical pickup on it's own? I would only need to run three wires to the engine (motor and ground for the lighting).

[peteski]

As Victor Miranda used to say (I paraphrase): good electrical pickup results in smoothest running model.  Maximizing electrical pickup is especially important for steam loco models. I would recommend not to eliminate any any of the electric pickup locations (even if this results in a more difficult assembly). Having just the short tender pickup power will not be as reliable as it should be, and will cause frustration.

[brokemoto]

The above paraphrase of Miranda's Maxim as explained by ke  accurately describes what guides me when  running or working on N scale steam. 

I am assuming that Original Poster is not going to use DCC on these.  From what DCC users have told me, Miranda's Maxim as explained by ke goes DOUBLE for DCC.

As far as MP steam goes, it has been my experience that the old MP 2-6-0, that with the traction tyres and half wheels live tender, used to stall constantly, even on straight and level, at speeds below thirty SMPH.  Once I had substituted an all wheels live tender for the stock, the problem disappeared. 

My experience with the old eight wheeler is curious.  It had no traction tyre.  If you leave the stock tender, it will stall enough that it is annoying.  I did, however, acquire one that was in pieces for next to nothing.  The contact wipers for the locomotive were missing.  I put the thing back together, anyhow, and added a B-mann SPECTRUM USRA standard and weights,  It rarely stalls.  The newer, MRC, eight wheeler has an all wheels live tender and a traction tyre (as does the MRC mogul).  I have one.  It rarely stalls.  Usually, if it does, it is due to dirty track.  I have  several of the older eight wheelers, some of which have all wheels live tenders substituted, some of which have the stock tender.  I have only one mogul that runs.  It has the all wheels live tender.  I had another one, but some clumsy oaf knocked it to the floor.  It must have hit funny, because the Loc-Tite on the drivers broke and it is now good for parts, only.

When Con-Cor issued its USRA heavy Santa Fe, a number of purchasers stated that while there was allegedly contact in the locomotive, it was mostly non-functional.  They stated that it was all going through the tender.  Most stated that as  long as you kept the track clean and the contacts from tender to locomotive sound, it would run with little stalling.  I  never bought that particular locomotive.

The Kato Mikado, especially the older versions, benefits from weight in the tender, even if you do not add the traction tyred driver pair.

All of my MP Pacifics and Mikados still have the wipers, so I can make no statement about how they might perform with tender pick-up, only.  One  of my Mikados is the MRC version, the other two are the older versions.  I have one Pacific from MRC and several older versions.  I have done the tender swap on all of those.

From my experience and what I have read/heard, you might get away with tender only pick-up; you might not.  On N scale steam, you always want to err on the dise of caution.  I would guess that you would have the most trouble at slower speeds.  The MP does have a flywheel, a balanced one, at that, so at speeds above thirty SMPH, if you do lose contact, you might notice a hiccup as the locomotive coasts until it re-establishes contact.  In the end, if you can not get the wipers back into place (which seems to be a common complaint with these things), you  might try it, anyhow.  Your choices seem to be let it sit, where it is guaranteed that it will not run, or do tender pick-up, only, where there is a chance that it might run satisfactorily.  The caution here would be that you  not be surprised if it DOES stall frequently enough that it is annoying.

[jdcolombo]

While I agree that electrical conductivity is extremely important, if you are using DCC, you can work around the electrical pickup problem by using a keep-alive with tender pickup only.  I have done this with my ConCor Hudson conversion, and it runs beautifully, with no stalls, sound dropouts or hiccups.  If you are running DC, then I agree with Peteski and Victor Miranda: more pickup is better.  (Actually, more pickup is ALWAYS better, but I wouldn't hesitate to use tender-only with a keep alive in a DCC installation).

I'm not sure which Bachmann tender you are thinking of using, but in general, tenders with the "pointed axle in cone" truck design (like modern N-scale diesel trucks; Kato and the latest Bachmann tenders use these) provide excellent pickup as long as there is appropriate weight in the tender.  Older wiper designs (like the Walthers/LL Berk and my ConCor Hudson or the old MRC wiper design) aren't nearly as good.   

John C.

[mmagliaro]

I'd have to vote to stick it out and try to get those driver pickups working again.  I know they are horrid to reassemble, sorry, especially with that cover plate with the wires that always break off.

If you have it completely disassembled, replace those wires with super flex so they don't break off as easily.

I once did a very involved fix to an MP 4-6-2 to make those wipers easier to service as shown in the following two photos.  This is some tricky work, but it gets rid of the breaking wires problem and makes the cover plate completely removable, wipers and all, without everything coming apart and getting all bent up.







Oh, and as for the ConCor 2-10-2, the big reason the driver pickups seem to not be effective on that model is because the way they wired it, the driver pickup has to make a "round trip" through the drawbar and back before getting to the motor.  So if the drawbar contacts get intermittent, you lose not only the tender pickup but the driver pickup as well.
 

[peteski]

While I agree that electrical conductivity is extremely important, if you are using DCC, you can work around the electrical pickup problem by using a keep-alive with tender pickup only.  I have done this with my ConCor Hudson conversion, and it runs beautifully, with no stalls, sound dropouts or hiccups.  If you are running DC, then I agree with Peteski and Victor Miranda: more pickup is better.  (Actually, more pickup is ALWAYS better, but I wouldn't hesitate to use tender-only with a keep alive in a DCC installation).

I'm not sure which Bachmann tender you are thinking of using, but in general, tenders with the "pointed axle in cone" truck design (like modern N-scale diesel trucks; Kato and the latest Bachmann tenders use these) provide excellent pickup as long as there is appropriate weight in the tender.  Older wiper designs (like the Walthers/LL Berk and my ConCor Hudson or the old MRC wiper design) aren't nearly as good.   

John C.

I suspected that someone would mention DCC and a keep-alive circuit to mitigate poor pickup.  This is especially true for a short and light locomotive with a small tender. I would  maximize the number of pickup points instead of solely depending on an electronic workaround. Especially, since it is not like he has to add custom pickup wipers - they are already part of the model - just not easily reassembled.