All:
I've got a peculiar problem that I've never seen before in 40 years of model railroading, and I've not been able to figure this out. Your input will be greatly appreciated. First, here's the background facts.
I run HO DC only, track is all Atlas 100 NS flex, track turnouts are Model Power NS #4s (been in service 17 years and doing fine), ALL rail joints and feeder wire/rail connections are soldered, and I have four level loops with one train on each.
I run the diesel engines in pairs (two locos per train) on the three larger loops, 60- to 70-car trains per loop, and run them slowly (scale 10 to 15mph), and it takes between 2.5 and 3 minutes for each to make one circuit of its loop.
All of my engines are either Bachmann or Atlas Trainman, and they are not cross-paired by manufacturer - generally they don't like to work with each other.
The Bachmann engines are GP30s, GP35s, GP38-2s, SD40-2s, and FTs
The Atlas Trainman engines are GP38-2s and RS32s.
With all the engines I've discarded the DCC boards and the 2 headlights, installed one 3-13 volt directional soft white LED headlight on the front, and added 2 to 3 ounces of weight, per loco. No BFS is used.
The power for each of the 4 loops is one MRC Tech 2 Railmaster 2400.
And on loop #3 I have an ampmeter and a voltmeter connected.
The layout has been in an air conditioned room for 13 years.
Here's the problem. The trains (run almost daily for about 45 minutes) will operate for one to five months just fine, then on one of the loops (and this varies) all of a sudden the pair of locos (either Bman or Atlas Tman) will speed up to about 25 to 35mph for about 15 to 30 seconds, then slow back down for 10 to 20 seconds, then will do this again, and generally keep on doing it. I take these off and replace them, and the replacement locos do NOT do this. Also after the guilty loco pair sits a few days or more I put them back on a train and run them (on any loop), and they are fine for another few or more months.
This happens randomly on any of the 3 major loops. Weird behaviour.
And here's a kicker. When this happens on Track 3 I check the meters, and if on Tracks 1 or 2 I immediately pick up the loco pair and put them on track 3 where the meters are and have them pull that train (removing the existing 2 locos). With Bman OR Tman engines doing the "surge dance" on Track 3 the meters are always rock steady! With a pair of Tman GP38-2s it's .5 amp at 4 volts. With Bman engine pairs it's .25 amp at 4.5 volts.
Have any of you experienced this? If so please chime in. Also any guesses would be appreciated. I'm baffled.
If you have any questions ask away. Thanks for your help.
DougC
I've got a peculiar problem that I've never seen before in 40 years of model railroading, and I've not been able to figure this out. Your input will be greatly appreciated. First, here's the background facts.
I run HO DC only, track is all Atlas 100 NS flex, track turnouts are Model Power NS #4s (been in service 17 years and doing fine), ALL rail joints and feeder wire/rail connections are soldered, and I have four level loops with one train on each.
I run the diesel engines in pairs (two locos per train) on the three larger loops, 60- to 70-car trains per loop, and run them slowly (scale 10 to 15mph), and it takes between 2.5 and 3 minutes for each to make one circuit of its loop.
All of my engines are either Bachmann or Atlas Trainman, and they are not cross-paired by manufacturer - generally they don't like to work with each other.
The Bachmann engines are GP30s, GP35s, GP38-2s, SD40-2s, and FTs
The Atlas Trainman engines are GP38-2s and RS32s.
With all the engines I've discarded the DCC boards and the 2 headlights, installed one 3-13 volt directional soft white LED headlight on the front, and added 2 to 3 ounces of weight, per loco. No BFS is used.
The power for each of the 4 loops is one MRC Tech 2 Railmaster 2400.
And on loop #3 I have an ampmeter and a voltmeter connected.
The layout has been in an air conditioned room for 13 years.
Here's the problem. The trains (run almost daily for about 45 minutes) will operate for one to five months just fine, then on one of the loops (and this varies) all of a sudden the pair of locos (either Bman or Atlas Tman) will speed up to about 25 to 35mph for about 15 to 30 seconds, then slow back down for 10 to 20 seconds, then will do this again, and generally keep on doing it. I take these off and replace them, and the replacement locos do NOT do this. Also after the guilty loco pair sits a few days or more I put them back on a train and run them (on any loop), and they are fine for another few or more months.
This happens randomly on any of the 3 major loops. Weird behaviour.
And here's a kicker. When this happens on Track 3 I check the meters, and if on Tracks 1 or 2 I immediately pick up the loco pair and put them on track 3 where the meters are and have them pull that train (removing the existing 2 locos). With Bman OR Tman engines doing the "surge dance" on Track 3 the meters are always rock steady! With a pair of Tman GP38-2s it's .5 amp at 4 volts. With Bman engine pairs it's .25 amp at 4.5 volts.
Have any of you experienced this? If so please chime in. Also any guesses would be appreciated. I'm baffled.
If you have any questions ask away. Thanks for your help.
DougC