I was reading in an old thread here that if you run several DC engines together as an MU you could blow up your power pack. I frequently do this, run several of my old Atlas Yellow Box or Classic locos back to back. Sure, one is pulling a little and one is pushing a little, but I don't race them hard this way and I only let them have ten or twenty turns around my (relatively short) mainline loop. I've never seen smoke issuing from the throttle.
The thread said that older transformers could only handle about 1 amp, and that each DC loco would draw about that, so that having two on the track together could max out and damage the power pack.
I have two throttles hooked up. One is an old Troller Transistorized Autopulse Transpak 2.5. I assume this is 2.5 amps but it doesn't declare this anywhere.
The other is a Railpower 1370 made by Model Rectifier. I don't see any info about amperage anywhere on it. Here's a shot of the back:
I know NOTHING about amps and volts, and don't even talk to me about ohms. I can only follow specific instructions, and it's a wonder my layout runs (it runs well!), given my ignorance.
So my question: Am I safe running two engines with either of these? Sometimes I actually run three ahead of 17 cars and a caboose.
Thanks,
-Matt
Returning to model railroading after 40 years and taking unconscionable liberties with the SP&S, Northern Pacific and Great Northern roads in the '40s and '50s.
Matt.
You could safely run a half dozen or more HO locomotives with that pack. The worse thing to happen is the internal breaker tripping if over loaded.
Pete.
yup, pretty much is the internal breaker [it -should- have one] would trip and then reset if you have too many loco on there ...
first sign would be that the consist stops for a moment, and then goes again ..
That's good news. So I've got the highball. Thanks!
Matt, whoever said that did not mean "old" like in 1980 or 1990, they meant "old" like in 1960.
Second, that pack has pretty good power, almost 2 amps, that will run most any 2 or 3 DC locos made in the last 40 years.
Take it from me, rembemer I am a DC operator still, and an electronics person, you are fine.
I use 4 amp power supplies on my wireless DC throttles and run lots of trains with four powered units, and barely get close to drawing 2 amps with some of my oldest equipment.
Relax and keep having fun.
Sheldon
crossthedog The other is a Railpower 1370 made by Model Rectifier. I don't see any info about amperage anywhere on it. Here's a shot of the back: -Matt
A listing from a 2000 catalog shows the MRC RAILPOWER 1370 (total amperage 1.5 with power for 4-5 average trains, with a overload light indicator).
Thanks again, guys.
MRC. Ran an add for those Tech II power packs where they had 20 or thirty HO engines pulling a prototype 40' tank car. Doubt very highly you will ever get to taxing any of yours to that extend.
shane
A pessimist sees a dark tunnel
An optimist sees the light at the end of the tunnel
A realist sees a frieght train
An engineer sees three idiots standing on the tracks stairing blankly in space
I've run 80 car trains with five locomotives on a 2.5% grade (over 45' long) with no difficulty.
I've also run locomotives to amuse grandchildren...place one diesel on the layout, with the lift-out at the entry door in-place, then, when they're racing around to watch it, I add another locomotive, and continue to do so until there are over a dozen in motion, some having caught-up to the others.To control the frenzy, I then begin to lift-off locos as they pass by my location, until we're back down to just one running.
I doan git no 'splosions
Wayne
Just to be sure, though... periodically put a hand on the powerpacks to be sure they aren't overheating. Most of the time they get too hot to touch before they relent and let the magic smoke out.
You might discuss the locomotives you're wanting to operate. While unlikely, there might be a chance they are drawing excessive amps and you probably don't want to go through the rigmarole of finding that out.
OvermodYou might discuss the locomotives you're wanting to operate. While unlikely, there might be a chance they are drawing excessive amps and you probably don't want to go through the rigmarole of finding that out.
I have a pair of Northern Pacific YB F7s, bought separately on eBay -- a very old one made in Austria by Roco and one made more recently by Kato in Japan. If I put them on opposite ends of the loop and run them at the same time one of them will eventually catch the other, but it would probably take 7 or 8 laps to do that. Because of this difference in the motors, I have been cautious not to run them as a mixed unit consist very fast or for very long, but I do like the look of back-to-back F units. (And to speak to something I keep seeing on the forum here, it is completely untrue that you have to rewire one of them to run them this way -- they both go in the same direction along the track no matter which way they are facing).
Another MU I like to do is two Atlas RS-1s, one a yellow box Japan-made Kato, the other a black box "Classic". Again, they don't run quite at the same speed, so I don't race them, but they look great together.
I also have a Bachmann Erie F-unit someone gave me for free that runs very nicely (PLUG: ever since my LHS guy reattached the thingies to the worm gears FOR FREE) and is a real looker, so sometimes I throw that behind the two NP F-7s or behind the two RS-1s, and pull 17 or 20 cars around the loop real slow, but at that point the engineer in the lead cab is so close to the conductor in the caboose in front of him that they can kibbitz on the crossword.
In my opinion, it doesn't really mattter much if there is a slight mismatch between unit operating speeds of similar units -- at worst you'dd see some wheelspin on one or the other if the load on their drawbar gets too much. These aren't synchronous motors that have trouble if not running close to their design electrical 'slip'...
When they say 'rewire' they simply mean reversing the motor leads on one unit (if you have a preference, the unit that will 'trail') which will make it move the opposite direction. This isn't something that DCC is 'aware of', to my knowledge, so even with decoders programmed to match speed the two units will go the same way back-to-back/cabs-out.