Electronics and DCC

Hi once again,

I started testing the lower level trackage and 2 % incline (from main to lower level) on the HO scale DCC layout under construction.

The three diesels - all BLI Paragons (switcher & RSD 15s) worked beautifully in all regards.

The steamers - all BLI Paragons (2-10-2, 2-10-4) worked beautifully up/down the incline until they hit a curved section between two turnouts.  Then they stopped, and would occasionally let out a loco engine sound.  I manually pushed them a couple inches either way, but they still would not move on their own and the loco sounds were sporadic at best.

The section of track has its own feeders (correctly wired), all the track in question is super clean, and the curve radius is well over 25 inch (close to 27).  The turnouts are Atlas code 100, the DCC is the Digitrax Super Chief.

The strange thing to me is that the small wheelbase SW7 switcher goes thru this area flawlessly at any speed, and the RSD's do the same.   Yet the steamers pretty much stopped once they got past the first turnout.

Maybe the steamers will have to live out their days on the main level if I can't get this resolved.  Anyone have any ideas - perhaps something pertaining to the steamers (10 drive wheels), or ????

Ha, I just knew things were going along too smoothly........

Your thoughts would be appreciated!!!

Mobilman44

Sounds like its binding on too tight a radius curve.  How drivers are blind?

It shouldn't be binding - unless the "curved section" creates an S-curve?? A BLI 2-10-4 can do a 22" R curve (at least mine can) although they recommend 24"R or higher. I'd say it's about 99% probable that it's an electrical issue, not a mechanical one.

Since you say it's "a curved section between two turnouts" I assume there a reverse loop issue involved?? Could be the length of the engine is causing a short of some kind - that is, the front driver might be in contact with the rails the same time the rear truck of the tender is still in a section with reversed polarity for example. It wouldn't affect a diesel with it's shorter wheelbase.

Or it could be the tender or engine is shorting out at a frog??

mobilman44:

Hi once again,

I started testing the lower level trackage and 2 % incline (from main to lower level) on the HO scale DCC layout under construction.

The three diesels - all BLI Paragons (switcher & RSD 15s) worked beautifully in all regards.

The steamers - all BLI Paragons (2-10-2, 2-10-4) worked beautifully up/down the incline until they hit a curved section between two turnouts.  Then they stopped, and would occasionally let out a loco engine sound.  I manually pushed them a couple inches either way, but they still would not move on their own and the loco sounds were sporadic at best.

The section of track has its own feeders (correctly wired), all the track in question is super clean, and the curve radius is well over 25 inch (close to 27).  The turnouts are Atlas code 100, the DCC is the Digitrax Super Chief.

The strange thing to me is that the small wheelbase SW7 switcher goes thru this area flawlessly at any speed, and the RSD's do the same.   Yet the steamers pretty much stopped once they got past the first turnout.

Maybe the steamers will have to live out their days on the main level if I can't get this resolved.  Anyone have any ideas - perhaps something pertaining to the steamers (10 drive wheels), or ????

Ha, I just knew things were going along too smoothly........

Your thoughts would be appreciated!!!

Mobilman44

My guess is that your steamers are high or low centering on a too-sharp vertical curve in your trackwork.  Most model steam locos are rigid frame - the driver axles cannot move in the frame to follow any dips or rises in the track.  All too often the transition between flat and grade is too steep (too sharp a curve) for a long rigid base to keep all drivers in contact with the rails.  If this is the case, at the top of an incline you can actually very slightly "rock" the drivers so that 1st the front and a middle set touch the rail, then a back and middle set touch.  At the bottom you have the opposite case - only the outer 4 drivers are touching with the middle sets hanging in the air.  And if you have carefully watched a rigid frame 0-4-0, you realize that often only 3 of the 4 drivers are touching at any time, even on what appears to be flat track.  Thus, at the bottom where the grade begins, your 2-10-4 may only have 3 of 10 drivers touching at a given time.

The cure is to use more of a transition between the grade and the flat area.  It should never be less than the length of your longest rigid wheel base, and twice that length is usually the minimum for good performance.  Even if they maintain electrical contact, the wheels not touching represent lost tractive effort.

my thoughts

Fred W 

 Mobileman

  Make sure the plug from the tender is plugged firmly in the loco. Use the last hole in the draw bar and make sure the foot plate between the engine and tender is above the plate on the front of the tender. My J1 did the same thing. When I placed it on the track the pivoting foot plate was under the tender plate and was lifting the side of the tender off the rails and was losing contact.

       Pete

mobilman44:

...up/down the incline until they hit a curved section between two turnouts...

This seems to me to be the source of the phenomenon you report....the track between the turnouts is often dead.  Unless you have that section fed by its own feeders, you are relying on joiners and perhaps weak or intermittent jumpers or wipers, maybe even only contact between points and stock rails, to power what lies between the two turnouts.

Try the run again, and when you get a stall, use a multimeter to gently probe that track section between the turnouts, and while you are at it, check all exits of the turnouts..both of them.  You may find that at least one part is dead.  If you find that there is power, then the answer would be solely with the engine.  It is losing connector contact as suggested above, or one critical axle is being lifted away from the tracks and you don't get proper power through to the decoder.

-Crandell

 Good news/Bad news.

Good news:  Your 10-coupled locos will find every S curve and faulty track work on your layout and will let you know what to fix for reliable operation.

Bad news:  Your 10-coupled locos will find every S curve and faulty track work on your layout and will let you know what to fix for reliable operation.

David B

Hi!

Thank you all for the excellent advice & comments.  I'll look on them this afternoon, as we will be visiting my wife's Mother (under Hospice care) this morning.  

I've had a lot of MR experience, and have found that an 8 or 10 drive wheel steamer will test your track and wiring to the max.  Quite honestly, if I didn't have the wonderful memories of the prototypes I would be all 1st generation diesels. 

I'm fairly certain I'm getting a short from the locos, and need to do some very slow running to pin it down.  I first thought power wasn't getting to the trackage as it should, but that area does have its own feeders, and of course the diesels go thru it flawlessly. 

Thanks again,

Mobilman44

Hi mobilman44,

Sorry to hear of your problem, it sounds like one I had on a previous layout. On a curve (24") the contacts on the wheels were not touching on the wheels on the outside of the curve. A little persuasion (bending) and the problem was solved.

ukrailroader

Hi!   I do believe I've found the main problem, but not sure how best to handle it.

I ran a new BLI Paragon 4-8-4 over the trackage and it worked beautifully.  I then checked out the two 10 driver locos and tried them again - only this time they stopped (and occasionally chuffed) on straight tangent track.  Yikes, what the heck is going on here ????

Well, after checking out the three locos again, it looks like the wiring harness "plug" for the 4-8-4 goes all the way into the loco's outlet.  The plugs on the 2-10-2 and 2-10-4 appear to go in a bit over half way.  I have tried to gently rock them in, but to no avail.  I really don't want to return them to BLI for repairs as its a good 6 week wait.  But if I can't fix them, then I guess I will resort to that.......

Any ideas?????

Mobilman44

 Those connectors can be a real PITB. The best suggestion I can make is use a small screwdriver and CAREFULLY push in, alternating between sides. Carefulyl ebcause ifit slipps off the outside - you'll probably gouge the plastic of the loco somewhere. If you slip to the inside, you can slice off a wire. You need about 6 hands to hold the loco, tender, screwdriver, and push on it.

 Before applying pressure, pull the plugs apart and check the pins on the loco side and make sure they are not bent and all stick out the same amount. Then check the sockets in teh plug and make sure one hasn't been pinched shut, they shoudl all look the same.

                                    --Randy

My sure-fire method if the quick prod with the butt end of a bamboo kabob skewer doesn't get it seated is to open needle-nosed pliers and place the tines on either side of the wires, against the plug body.  I then give a good levering press and that always seats the plug firmly.  I cured my Rivarossi Allegheny and my PCM Y6b (the latter notorious for a plug that works its way loose) by using those pliers.  I found that the rocking press, first on one side and then on the other, didn't get the plug any further in.

-Crandell

Hi!

Thanks all, I solved the problem.  It turned out the 6 holes in both tender wire harness plugs were "stopped up".  I used a # 72 and #74 drill bit and carefully cleared each of them.  This solved the problem, and the two locos run like a charm!  Andddddd, they made it thru all the lower level and incline trackage without a hitch.

Its a shame that one can pay $295 plus shipping for each of two locos and have a problem like this.  But, I have to say they now really look, sound, and perform just great!

Mobilman44

 Mobile, glad you found the problem.

 A trick I learned from Larry at BLI is most of the time the power lead from the tender to the engine has the same plug on both ends. When I got my Y6-b it could not keep the plug in the engine. I turned the plug around and I was good to go.

         Cuda Ken 

Cuda Ken,

   I'm not sure I follow what you mean by turning the plug around.  Does it detach from the tender sourced wires to allow you to do that, or ?

Its early, the coffee hasn't kicked in, and I haven't seen rain in a month - so please pardon my ignorance!

Mobilman44