PROBLEM: HO scale layout won't stop shorting out

[NILE]

I have room size oval HO scale layout that has been operating for three years.  I'm running a DB150 command station with no bosters and now I can't seem to have a train run further than half the layout.  I though maybe I was trying to run to many trains at once, I had four trains with seven engines.  I am pretty sure I have run four trains before without issues. 

Three trains had two units MU'd together (6 total, 2 with sound) and the other train was running my MTH Yellowstone with sound.  The trains would move a few feet, and then short.  The short would be 5 beeps and would not clear itself.  This problem started when I added the MTH unit, so I took that one off.  Same problem. 

I'm now down two three trains with four engines, only one sound and only two MU'd and I'm still having the same problem.  Although now the train will run 1/2 the layout before it shorts.

I have had to reconnect a few feeder lines in the past week, but that shouldn't effect anything. 

The DB150 advertises that it can handle 22 engines, but I'm having issues with just four.  There are a handful of engines in the engine house, and that is power on.

     Is the DB150 getting old?

     Am I overheating something?

     Is a peice of rolling stock dragging something causing the short?

I'm at a lost...

Thanks,

NILE

    

[woodone]

So all your trains stop at the same time? How are you clearing the short?

I would start with one unit-if it runs add a second-if they both run add a third and so on until the short shows it self- are these units stopping at the same time yet at different places?

[PennCentral99]

NILE

I have had to reconnect a few feeder lines in the past week, but that shouldn't effect anything.

Thanks,

NILE

This is where I would start. The last change is usually where something went "wrong". Are you sure one of the feeders didn't get reversed?

Terry

[RR_Mel]

Do a regular trouble shooting procedure.  Remove everything from the track and check to make sure there are no shorts.

Place one locomotive on the track all by its self and see if just one locomotive works OK, do several loops with the locomotive.  If that works put a second locomotive on the track and see if two work OK.  Again do a couple of loops.

If that works OK place a third locomotive on the track and do a couple of loops.  Keep putting one piece of equipment on the track doing a complete check until you find the guilty culprit.  

 

Mel



 
My Model Railroad   
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.

[rrinker]

 You'll never run 22 locos with just the DB150, not in HO or larger. The DB150 can supply 5 amps. that's more like 10-15, depending on the loco age and how many have sound. If you have nothing but Stewart/Bowser Baldwin switchers (VO-1000, S-12, VO-660, etc) - you might actually get 22 of them running without exceeding 5 amps. They are very low current draw locos.

 As stated, you need to do a process of elimination. What was the last change you made before this problem started? Take ONE loco - run it by itself, does it make it around the entire layout without shorting? If not, does it always short at the same point? Look for gaps that might have closed . Once you get one loco that works 100%, try a second one - alone. When you get a second oen that is 100%, run these two together. It still should be fine, if the two were fine on their own. If not - what locos are these, and what couplers are on them? Athearn BB locos in particular, if using metal couplers (like Kadee #5) in the couler box cast into the frame, can short through the couplers if the two locos are places ont he rails facing opposite direction and coupled together (two road switchers with the fronts facing out, or AA cab units coupled back to back, etc). This cna even develop over time as blackening wears away on the couplers.

 Somethign else to check is to make sure your power supply is good. Under load, with trains running, the input terminals of the DB150 should be close to the rated voltage of whatever power supply you are using. Also be sure the power supply is one rated to power 5 amps, using a less than 5 amp power supply with a 5 amp booster can result in odd behavior as the power source voltage drops under load.

 ANd make sure address 00 is on speed step 0. The DC offset of using address 00 can sometimes cause issues with locos that have noise supression capacitors in them. 

                                              --Randy

 

 

[MisterBeasley]

The DB150 puts out 5 amps.  I would say that's low for 22 engines, particularly with sound.  But, it should handle 5-10 engines easily.

Engines in your yard or service facility count a bit if they're running.  So do illuminated passenger cars or anything else you're running on track power.

Have you divided the layout into power districts, each with its own breaker?  If so, you probably don't have the full 5 amps available to any individual district.  You have to look at the district boundaries and the breaker limits for each district to see what you really have available.

[NVSRR]

Question. Do any of them stop at the same spot?

 

it almost sounds like the breaker in the DB150 has gone bad. less current draw, some what further travel before it trips.  Reduce draw and same thing happens.  

you could also have a loco or something that has a slow leak short.   Where the short has a high enough resistance to not cause a draw to trip a breaker but with added draw elsewhere it does create a over current draw.   Those can be tough to find. 

do you have an ohms meter to monitor the current draw?

shane

[BigDaddy]

NILE

Is a peice of rolling stock dragging something causing the short?

That is one of the reasons people have suggested taking everything off.  You should inspect each car as you do so.  We aren't going to be able to see that from here.

[rrebell]

The list is endless but disconect all the work you just did and see what happens. Also any time a short occures gremlins can sneak in, make sure all your insulating points in the rails are still valid.

[NILE]

The trains do not stop at the same spot, it appears to be random.  If it is the DB150, can the breaker be replaced in the unit?

I don't have power districts or boosters.  My layout is wired all as one peice.

I took all my engines off, but kept the rolling stock on.  I did take off one passenger car that uses track power for lights.  It seems that I can run up to four engines without issue.  The trains opperate like normal.  Once I add the fifth then it will last 30-90 seconds then the layout shorts out.  If I remove the fifth unit, the problem seems to go away.  At one point, I was running three units without sound and one with sound and it still seemed to work fine.  Until added the fifth unit.

I know I have had multiple trains with multiple units mu'd before, maybe up to eight engines.  However, I wouldn't run four trains at a time by myself.  So it occured to me, that I might not have ever run this many engines at the same time time.  I usually have two trains running, or one train running and a second doing switching at most.  That could easily be 3 to 4 engines.  That being said, it still seems like something has changed.  I have had the DB150 for many years... maybe it is showing its age?

[Trainman440]

If each engine individually runs fine by itself, but not when all are powered at the same time, and they arent stopping at the same point, then it sounds like the booster cant handle all engines running at the same time. MTH engines have a reputation for drawing more current than most. Id recommend getting an ammeter and monitering the current draw. From there, you can see whether or not there's a pattern for the "shorting out". Like for ex if everytime the current draw spikes the booster cycles. Or who knows, maybe your 7 engines draw more current than you previously thought. I dont think Digitraxx(?) meant large articulated steam engines with smoke units when they said 22 engines.

I dont think anything is shorting per se, but the booster is unable to supply the current necessary for all engines and is as a result, shutting off and restarting. This happens to my NCE powercab too when I have too many passenger cars with large capacitors built in, which all need to be charged up. 

PS I think when it said run up to 22 engines I think it meant it can only control/communicate with up to 22 engines at once with its signals. I dont think it meant it can POWER 22. 

Hope this helps,

Charles

Edit: and by booster, I meant command station. oops

 

[Trainman440]

This was taken from digitrax's website. It seems like its very temperature sensetive. 

Technical Note About DCC Booster Output Ratings: Digitrax boosters have maximum output current limits of either 5 or 8 amps. The actual continuous output current that your booster will provide to the layout depends on several factors including the input supply voltage, the ambient room temperature and air flow over the booster's heat sink. Higher input voltages increase the amount of heat that must be dissipated by the booster's heat sink. If the heat sink does not get enough air flow to allow for heat dissipation, the booster will eventually reach an over temperature state and shut down. A small fan blowing across the heat sink on your booster will increase the maximum sustained current output capacity of your booster.

Each DCC company specifies the output capacity of its boosters according to their own internal standards. Tests designed and performed by several model railroaders have shown wide variations in the actual output capacity of DCC boosters. In most cases the tests were designed to overload boosters and cause them to shut down. The conclusion based on these tests is that each manufacturer uses a different way of determining booster output capacity, Digitrax tends to be more conservative in stating booster output ratings. The factor that is most important for achieving maximum output capacity is the booster’s heat sinking ability. In these tests, Digitrax boosters have demonstrated excellent heat sinking capabilities and the ability to consistently output the advertised 5 or 8 amps when appropriate fans are added in high temperature situations.

[richg1998]

NILE, there is diference between a short and a high load with a booster.

Below is a five amp DCC amp meter I built some years ago. One for me and one for the club I use to belong to. Accurate. Mine used the 20ma DC scale on a Harbor Freight multimeter. The two chips do the conversion.

http://www.circuitous.ca/DCCammeter10.html

Rich

[selector]

NILE

;;;

The DB150 advertises that it can handle 22 engines, but I'm having issues with just four.  There are a handful of engines in the engine house, and that is power on...

   

     Am I overheating something?

    

Thanks,

NILE

    

I don't believe this to be true.  The Digitrax can keep tabs on as many as 20? addresses, but only in memory.  It has a 'stack' that can have up to 20 addresses, maybe it's more these days.  You're supposed to purge addresses from the stack as you remove locomotives and place others on the rails.

I have never read in my manuals, to my recollection, that the DB150 can run 22 locomotives because the engineers designing the system had no way of predicting what the amperage draw of any grouping of 22 locomotives would be.  The range might be as much as 3 amps across groupings, greatly exceeding the rating of the DB150 and/or its proffered power supply.

[mbinsewi]

selector

I have never read in my manuals, to my recollection, that the DB150 can run 22 locomotives

Correct.  The maunual does say:

"For example a 5 amp booster and power supply will operate between 10 and 15 average N-scale locomotives and between 6 and 10 HO locomotives. If you wish to run more locos on your layout, then you will need to set up more power districts to provide more total power."

Mike.

[rrinker]

 Based on the OPs last test with 4 locos, 5 causing the shutdown, I highly doubt the DB150 is being overloaded. I've had more locos than that running on my original Zephyr, which only has half the capacity (2.5 amps) with no problem, other than trying to keep them from running in to one another since I didn't hjave enough throttles for each loco. I was trying to see just how many it could run. It was kind of like the scene from the I Love Lucy show where Lucy and Ethel are working in the candy factory.

 What I would liek to try next, is mix and match the locos - if it shuts down with 5, take one off and put a different one in place of one of them. If it still shuts down, put the one just taken off back on, and take another of the original 5 off - what I'm getting at here is that if this used to work fine, somethign has changed - and that something could be that one of the locos has developed a problem and is drawing excessive current. Unless these are all old Athearn BB locos converted to DCC, you should be able to run way more than 5 with a DB150. Almost certainly more than 10 if they are all made within the past 10-15 years. But just one drawing a lot of extra current (but that might fry the decoder, too), or a coupel of them drawing say 50% more than they used to, still within what the decoder can handle, can change how many can run at one time. Could be all of them - how much run time have these locos had since the last time the gears were cleaned and greased, and the bearings oiled?

 And it would be good to test the voltage of the power supply - at the input of the DB150, to see if the fault is there. Check the voltage when no locos are running, and again with 4 and 5. It should be still at or near the rated voltage. If it's dropping down, the fault may be the power supply, not the DB150.

                              --Randy

[NILE]

So we went back the layout and tried to conduct some controlled tests.  Three engines and it ran like a champ.  I added one engine and still no issues.  I am running these engines indepdantently, none are consited together.  When I add the fifth, I can run trains for about 45 seconds and then it shorts out.  Sometimes it will last longer, maybe up to a minute and 15 or 30 seconds.  I think that is based on the engine I use.  If it is an old blue box athearn or sound engine, it last shorter.  That makes sense as thouse engines draw more amperage.

The more I think about this problem the more I think about how I've been using this layout.  I rarely consist more than three engines together at time, even though I have done speed matching when I get three together they don't always work well.  So most of my trains are two engines mu'd.  If I am running the layout by myself, I would usually have one train running the main and a second switching the yard.  That would only be 4-5 engines, and the one switching the yard wouldn't run for more than 45 seconds as my yard isn't that long.  When my son is running trains with me, we might only have two trains on the mainline and another one working the yard, so again 5-6 engines but not at the same time for more than 45 seconds.  So its possible there isn't a problem, I just haven't taxed the system this much before.  Thoughts?

Notes:  I know there are some wiring issues and at least one dead spot.  The track work isn't the best either.  I haven't put a lot of effort into fixing those as we are moving this summer, so the entire layout is coming down anyways. 

Questions:

If I add power districts to the next layout, I'm still limited to 4-6 engines per distritct because of the amperage?

Is the DB150 getting old and need to be replaced?

Will the new DB210 or DB220 be compaitable with my old DB150?

[maxman]

NILE

So we went back the layout and tried to conduct some controlled tests.  Three engines and it ran like a champ.  I added one engine and still no issues.  I am running these engines indepdantently, none are consited together.  When I add the fifth, I can run trains for about 45 seconds and then it shorts out.

As an observation, there is a difference between "shorting out" and "overloading".  From your description it appears that the system is being overloaded.  If you have an ammeter you can put it in series with one of your track power leads and determine how much current the locomotives require.

[Trainman440]

Yea, Id seriously recommend getting a multimeter and monitoring the amperage used by all the engines. You might find:

1. certain engines are drawing an oddly large amount of current. Maybe its time to lube the motors and gears to decrease current draw. If this is the case, the DB150 is fine, and one or more of your engines need some inspection. 

or 

2. You DB150 is shutting off when the current draw is far less than 5 amps. In which case, you might need to replace it. 

Charles. 

[rrinker]

 If the DB150 has failed, the replacement choices are limited, because the new DB210 and DB220 are strictly boosters, they have no command station capability. 

 The Zephyr Express has the same 22 loco capacity, plus a much improved command station functionality, including a dedicated program track that can read as well as wrote, and a computer interface built in. But it only puts out 3 amps, not 5, so you might need an additional booster like a DB210.

 The DCS240 is WAY overkill for all but the largest clubs. The DCS210+ is the idea replacement - command station with 5 amp booster, but Digitrax does not sell that separately. You can only get it in a set - if you want a new DT600 throttle, you can get the full set.

                                     --Randy

 

[ef3 yellowjacket]

Among the other possibilities, you might take a hard look at your track.  Isolate a section at a time; the one in question is where I would concentrate my efforts.  A relatively consistent occurrance in a section, and good running else-wise is an indicator of track problems.  This should be

mostly common-sense stuff; just take it one step at a time.

Rich