If the wheels are still failing to contact the rails as the loco moves, then I would say that a physical/mechanical issue is the root of the problem.
We’ve talked about several possibilities. Uneven track, or the wheels/flanges being affected by being too narrow or too wide causing a lift for some reason.
If someone has thought of other possibilities, now would be a good time to speculate.
When these kinds of issues come up in these kinds of threads, there is a need to eliminate as many causes as possible - - - the process of elimination.
As I said in an earlier reply, the problem here is that we have all been unable to eliminate any possible causes, so it could be the loco itself, the turnout, or an electrical issue. So, let me repeat three possible approaches to narrowing down the list of possibiities.
What happens if you physically turn the loco around and run it throught the turnout from a different direction? Try to locate the exact spot on the turnout where the stall/short occurs.
Are both the front and rear trucks picking up power from the rails? I have seen this more than once where either the front truck or rear truck is not picking up power.
Is there power between the frogs shown in that earlier photo with the loco laying on its side? When I have experienced a problem like stalls at slow speeds over turnouts, I will get out some test wires with alligator clips at both ends of the wires. Then, I will connect one end to a straight section of track and touch the alligator clips on the other end to various rail segments on the turnout to see if the loco will move.
At the moment, we are at an obvious impasse.
Rich
The stalling is random. I have trouble repeating the stalls to narrow down the issue. Have narrowed it down to happening between two turnouts close together like a crossover or two turnouts connected together.
Front and rear trucks are picking up power but I am guessing all the wheels on the trucks are no getting power or wouldnt have this problem.
According to the volt meter there is power between the turnouts.
Random implies intermittant electrical contact cuased by the weight of the locomotive.
In your picture, if that is exactly where it stalls - the top side (conductor’s side - I was going to say fireman’s side but since it’s a modern loco…) rear truck, to the right of the pic, could have all 3 wheels on questionable track, since the only power to the point and closure rails is via the point rail contacting the stock rail.
The other thing I saw mentioned - if there are gaps in the rails past the frogs, are there feeders to the rails between those turnouts? Otherwise, that entire section is dead as a doornail. It’s perfectly fine to have feeders on the frog side of even an Electrofrog turnout - AFTER the gaps. In fact, you pretty much have to,especially in a crossover arrangement, or the track past the gaps is completely dead, unless backfed via the opposite side of the loop.
The easiest way to find out where the dead spot is, is to use a small flat screwdriver, and when the loco stals, touch various points with the screwdriver - when you bridge power from the powered part to the rail the wheels are on that has no power, the loco will start moving.
I would wire all Unifrogs to work like Electrofrog, with polarity control via switch machine contacts. The more rail in the turnout that has a positive power source, the more reliable it will be. The optional modifications to provide direct power to the point and closure rails also can’t hurt, especially for N scale.
–Randy
Here is a pic of the back side of a unifrog. The closure rails have jumpers to the stock rails. The rails after the frog point has one jumper from the stock rail the other from the straight closure rail.
Going to put feeders before and after the unifrogs in one section and see what happens.
Installed feeders on both sides of the problem turnouts that was pictured with the locomotive on its side. That seems to have done the trick. Ran the locomotive over it for an hour on speed step 1 both directions changed directions between the turnouts, sound off and on and it wont hesitate or stop. Looks like I have a ton of feeders to put in.
Glad you solved the problem. However, I thought you mentioned the wiring was okay?
Just for future reference because the unifrog’s are fairly new to the scene, do you think the problem was that you did not follow the wiring guidelines correctly (took short cuts), or do you have to add more wiring than the instructions call for? Just to help out future readers.
Does that mean before and after the turn out or right and left sides of the turnout?
More electrons, what’s not to like?
Yep, a lot of rabbit holes in this thread, warped turnouts, warped trucks, 6-axle locomotives, soldered rails, etc.
Turnout 101 Wiring: Add feeders on every end of every turnout. Even then, when stalling occurs on a turnout, check for continuity. I have a few Walthers Shinohara Double Crossovers with feeders on all four ends. But over time, some of the jumpers have failed resulting in unpowered rail segments.
As far as Unifrogs are concerned, they require no special wiring. I have four Peco Code 83 Unifrog Double Slips. No problems whatsoever. Just add feeders on every end of each double slip.
Rich
Agreed.
But its still a mystery as to why some locos were more susceptible to this and others were not.
If turnout joints are sold
Not much of a mystery. Exact wheelbase is not going to be the same, even if it’s two brands of the same prototype. Or maybe some brands of 6 axle units pick up with only 4 wheels on each truck instead of all 6. ANd in those cases - is it the two outside axles that pick up, or the two nearest the ends, or the two nearest the center? There’s enough minor differences like that between different brands of locos that allows one brand to hit a spot where both sides of both trucks are on dead spots, whereas another brand will always have at least one wheel on each side on live track and thus never stalls.
Could even be a pickup problem - in that it’s SUPPOSED to pick up from all 12 wheels but it’s not pickup up power from one side of one of the trucks at all because the pickup wipers aren’t making contact, or something. So with the extra feeders, there’s no dead spot for the working pickup to get stuck on, but if all pickups were solid, it wouldn’t have stalled in the first place. This is easy to test - put the lead truck on a piece of paper, rear truck on the rails, see if it runs. Repeat with the paper under the rear truck and the front truck on the rails. Any loco that says it has all wheel pickup should work fine with one whole truck insulated from the rail. Then you can see just how far you can go but putting one whole truck on the paper and then putting one, then two axles of the other truck on paper. As long as one pair of wheels is touching the track - it should work.
–Randy
What is the thought about putting dielectric grease on the wheel pivots? There is play in the wheel pivots or they would not turn. Maybe something to always conduct electricity even if the pivot is not touching the copper pickup.
The purpose of dielectric grease is to prevent corrosion not to enhance electrical conductivity.
In a motorcycle, if you have a male-female crimp on connector, there is part of the connectors that don’t make contact with each other, but if that area develops corrosion, it can spread to areas that do make contact.
There are conductive greases. 100% contact would be better.
Is it intermittent contact or a lack of power? Now that you have added feeders to all three ends of the problem turnouts, has that not solved the problem?
Rich
I did feeders at two problem turnouts. Going to do the same at another two and see if I get the same results.
The locos with pointed axles are doing ok. Got a BLI and it has straight axles with a lot of clearence and need to get better conductivity. It stalls on straight flat track.
I did feeders at two problem turnouts. Going to do the same at another two and see if I get the same results.
The locos with pointed axles are doing ok. Got a BLI and it has straight axles with a lot of clearence and need to get better conductivity. It stalls on straight flat track.
My original thought when reading this thread for the first time back on the first page was that the BL was probably going to be a bit quirkier than the other locos. If it has problems that the others don’t, there may not be much you can do about it. I thought it was best to be sure the track work was bulletproof before guiding you to start tearing into a loco when its design might make it a bit more tempermental when compared to KATO, IM, and Scaletrains.
We keep on coming up with more issues. This one is a bit easier to deal with than a stall on a turnout. This one is either a problem with the loco itself or insufficient power to the track.
If the BLI is an N scale Paragon 3, which I assume it is, there are known issues here, and those issues relate to the decoder. The Paragon 3 decoder is a proprietary to BLI, and it has performance issues.
If the “straight flat track” is the problem, it can only be lack of power which is most often caused by lack of sufficient feeders, followed by poorly fitting rail joiners, or dirty track.
Does the BLI always stall at the same locations or are the locations random?
Do any of the other locos stall on straight flat track?
Rich
I’ve had the same problem with Roco M-62 (6-axle diesel, DC, HO scale). The reason of problem was traction tires. Sometimes all non-traction tire wheelsets lost contact with the rails on turnouts, and only wheelsets with traction tires retained contact with the rails, and locomotive stalled. This also happened on curves with superelevation. I simply replaced traction tire wheelsets with non-traction tire ones, and everything became OK.
However, I just watched BLi SD70ACe exploded view, there are no traction tires, I have no idea, why it stalls on straight flat track. Maybe there is some glue on the rails?