Runaway MTH engines

GRJ is right.  Do not switch outside rail wiring.

If you can scroll the speed to 0 and stop loco, then do signal test.  Will loco startuo on that track?

I haven't had the time to test it yet, but the loco started up in certain positions on the track, and just part of it seemed unresponsive.  Weird, but power was still to the loco, it just stopped responding well to DCS commands.  When it was in the "spot", it would not shut down.

BTW, I found a link to a thread in OGR for people wiring whisker track with a variety of solutions.  Relays are interesting but need DC, I don't like rotary switches to power only one whisker at a time, but running heavier wire through heavier duty switches also has it's drawbacks.  Your opinions?

Thanks,

Tom

I just got off the phone with a very excited Barry B.  Excited that he caught me in an error.  I prefer to think of it as a senior moment.  I was thinking that the traction tires were on the same side of a diesel truck, but in fact they are on the same axle.  So forget about straddling turntable and spur being a problem if only one railway is grounded.

Tom, I don't have any drawbacks from using simple toggle switches on a diagram of turntable area.

Barry, Robert

Questions regarding powering spurs that occurred to me this morning:

Since I power my TIU separately through the aux power port, I first power up the TIU, then power up the Z4000 track power.  When does the watchdog signal get sent - when the TIU is first powered up, or when the track power gets applied to it's inputs?  IE, when does the 5 seconds start?

Therefore, if I start everything up with my whisker tracks unpowered, if I later power them up to move a loco, won't they NOT receive a watchdog signal since the TIU had been powered long before, and just start in conventional mode?  Do I have to power all track initially to get all locos the watchdog signal, then power down the whiskers?  Should I start everything in a different order?

Thanks,

Tom

You guys are up later than me

The TIU channel sends out the watchdog signal whenever it receives power on the input.  If you switch the power to one input, even though the TIU has been on for some time, you get the WD signal on that channel's output.

John,

The TIU channel sends out the watchdog signal whenever it receives power on the input

That's incorrect, particularly in the case of a Variable channel set to variable mode.

Tom,

when does the 5 seconds start?

When the voltage at a TIU output channel goes from 0 to a positive value.

Barry, just so I understand completely, anytime I switch power from 0 to a positive value at a TIU OUTPUT, a watchdog signal will be sent?

In my case, I only use 1 TIU fixed output for the entire layout, including the whisker tracks.  Therefore, if I understand correctly, if I power on my layout initially with the whiskers switched off, fixed 1 will send a 5 sec. WD signal to the layout.  Then, without powering the TIU up or down, if I just later switch whiskers on or off on the same fixed output, every time I switch one on, a new WD signal will be sent?  If the TIU output is already at power, how does it know the output has been switched on to a new branch of track?

Tom

Tom,

just so I understand completely, anytime I switch power from 0 to a positive value at a TIU OUTPUT, a watchdog signal will be sent?

Yes, that's correct.

if I power on my layout initially with the whiskers switched off, fixed 1 will send a 5 sec. WD signal to the layout

Yes, that's correct.

Then, without powering the TIU up or down, if I just later switch whiskers on or off on the same fixed output, every time I switch one on, a new WD signal will be sent?

No, that's not correct.

If the TIU output is already at power, how does it know the output has been switched on to a new branch of track?

It doesn't know and the watchdog signal is not sent.

OK, so the correct procedure is to power up everything initially, including the whisker tracks, then shut them down?  Won't they forget the watchdog signal if subsequently powered down?  Please explain how I can have switch controlled whiskers and also make sure that they all have the watchdog signal and will come up properly under DCS control?  I hope the answer is not that each whisker needs to be under a separate TIU output.  Many people seem to be doing what I'm talking about successfully, so I'm missing something in the explanation.

Thanks,

Tom

Tom, I don't power everything up and then shut it down.  Forget the watchdog signal.  When I want a loco, I turn on the siding toggle.  If the loco starts up, it will be in conventional so I just press the startup button.  If it doesn't startup, no problem.

I do set conventional sound volume higher than I run, to alert me that a loco is in conventional.

If a loco starts moving fast immediately on power up, and always in same direction, then this is another issue, namely that the loco has been locked in one direction.  I just had this happen on a new PS3.  Per MTH, this requires what is called by MTH a "conventional reset," which is done by 1 whistle push and 5 bell pushes.  But that's another story.

Robert,

I guess I don't understand this very well.  I thought it was imperative to start up PSX locos with the watchdog signal or they might start up in conventional and do unpredictable things, like go runaway, like several of mine have done. 

I've never run any of my locos in conventional - they are all PS3 except for one PS2.  The ones that went runaway were all PS3, but not recent PS3 like the EVO.  I don't even know how to lock a loco in a direction.

I'm looking for a bullet proof way to wire things and start them up to prevent bad things like runaways from happening.  I'm getting too old to handle that sort of thing.

Are you saying that sending a start up command sends a watchdog signal?

Is "conventional reset" the same as "factory reset" in the DCS menu?

Ton,

Won't they forget the watchdog signal if subsequently powered down? 

Yes, they will.

Please explain how I can have switch controlled whiskers and also make sure that they all have the watchdog signal and will come up properly under DCS control?

You can do as RJR suggests above. When you want to use an engine, turn on a toggle for just that engine's siding and then press Startup.

Alternatively, if you want to turn the engine on but don't want it to start up, press Shutdown instead.

The following, from The DCS O Gauge Companion 2nd Edition, page 167, may help:

If a PS2 engine comes up in conventional mode for any reason, the DCS operator has two options. If the operator desires that the engine be dark and silent, waiting for a DCS Start Up command to be issued, all that's required is to select the PS2 engine using the Engine Control Screen and press the Shut Down key. The engine will become dark and silent in DCS stealth mode, waiting for a future Start Up command.

If, however, the operator desires to put the engine into DCS command mode and then operate it, all that's required is to select the PS2 engine using the Engine Control Screen and press the Start Up key.

PS2 engine lashups, however, are the exception to this rule. If a lashup misses seeing the watchdog signal, pressing Start Up has no effect. For PS2 lashups to come up in DCS mode, it's necessary to do one of two things. The first is to power off the TIU channel to which the tracks where the lashup resides are connected. Then, if there's a toggle switch that controls the siding or track block where the lashup resides, this switch must be turned on before turning on power to the TIU channel to which the tracks are connected. Power must then be turned on quickly enough that the lashup catches the watchdog signal. The second is to first highlight the engine in the remote's Active or Inactive Engine list. Then, turn on the toggle switch and immediately press the thumbwheel to select the engine. It will come up in DCS stealth mode, dark and silent. This also works with individual PS2 engines.

If you have a copy of the book, you should read it. If you don't have a copy, you might find it to be a helpful purchase.

This and a whole lot more is all in MTH’s “The DCS O Gauge Companion 2nd Edition", available for purchase as an eBook or a printed book at MTH's web store!

Don't know if it's bullet proof, but per Barry's book, if the engine starts up in conventional mode (misses the watchdog signal) select the engine in the DCS remote and press the start up key. That puts it in DCS command mode. If you want it to remain silent, press the shut down key and it will just sit there until you start it up with a start up command.

A conventional reset with a transformer is not quite the same as a factory reset with the full DCS system.

I have never had a layout with sidings that I can turn off so I haven't tried it, but I am in the process of building one now. My Mianne bench work came yesterday and it's now all set up and waiting for me to go to Home Depot for a few sheets of plywood to finish the top. Hope to be able to try out the above start-up procedures very soon.  

Edit: Barry replied while I was typing this, obviously he knows much more than I do. The quote from his book is what I was referring to with the siding start ups. I also recommend his book, lots of good info in there.

From the engine's perspective, when it initially receives track power it looks at the track to see if there is any DCS activity.  If if detects DCS activity, it enters DCS command mode and powers up dark/silent waiting for a command (usually Startup).  If it doesn't detect this DCS activity it will start up in conventional.  The DCS activity does not have to be a Watchdog packet; it can be any valid DCS activity. 

As an aside, which might shed some light on, PS3 engines also perform a similar test on initial track power looking for a DCC signal.  If it sees a DCC signal it will power up dark/silent in DCC mode waiting for a command (usually Startup).  What's different about DCC is the TIU-equivalent continuously sends DCC packets even when nothing is happening.  So in DCC there is no discussion of watchdog packets - or lack thereof - when powering up spurs/sidings and having the engine come up dark/silent.

So in the second or so when a PS3 engine initially receives track power, it looks for a DCS or a DCC signal and if found comes up dark/silent in the respective command mode.  If it does not detect a command signal it comes up in conventional.

That said, yet another method to have the PS engine come up dark/silent upon initial track voltage is to attach a DCS Remote Commander (DCSRC) lock-on to a switched spur/siding.  These come in the MTH starter-sets or can be bought separately with occasional good deals on eBay or from someone who started with a DCSRC and has now moved up to the full TIU.  The DCSRC generates a watchdog signal when it initially receives power.  There is a rather involved, some might say tedious, discussion of this in the following thread.  But if you can get through the thread, you will by then certainly understand the DCS Watchdog concept!

https://ogrforum.ogaugerr.com/t...43#31980145128393143

In any event, IMO the runaway issue, while perhaps related, is separate from the Watchdog issue.

Barry,

I do have a copy of your book and I read the section you mention, but I felt the explanation didn't explain how to avoid runaways (3 locos at once taking off evidently in conventional mode).   When will your next version be out?

It's now apparent to me that the only way to handle that is to have a toggle on each whisker track, and not toggle it on until I've selected the loco on the DCS remote, and am ready to start it, shut it down or otherwise manage it.  When I had the triple runaway, I had power to all the whisker tracks and all 8 locos, something happened to cause the runaways, and the problem occurred.  I've got some wiring to do!

I really appreciate all the input and help I've received here, and the patience everyone's had with my questions. 

Out of curiosity, how do I tell my PS3 locos that, if they start in conventional, to start in neutral?  Is that in your book somewhere Barry?

Tom

Here's a schematic.  I did not "analyze" the hirailer suppressor as my interest is in the detection/understanding of the surge/transient issue.  TVS devices suppress/absorb surges.  Thus, the clamping (Zener) diodes used within are rated with power capabilities over 1000 Watts.  The clamping diodes I used in the detector (13 cents each at DigiKey) are rated a measly 1/2 Watt and simply pass low power to the red detector LEDs.  While suppressing transients using TVS devices is inexpensive and perhaps routine, if transients are made worse by wiring or layout issues I'd want to detect and fix them rather than (or in addition to) masking the problem with suppressors. This is just my opinion.

Thanks stan2004,

I think I will make one of these. I have all the parts but the 1N5257B Zener's, looks like I need to start another order at Digi-Key. I think I have some 1N914's or something like that in addition to the 1N4xxx's, would that be a valid substitute for the 5257's, I don't know the specs on either without looking them up, then still may not get something right in the comparison?

Didn't the hi-railers suppressor also indicate surges? I didn't fully understand what it was doing, but was thinking it also had LED indication of a surge?

Thanks for the schematic! I will also try to fix anything I find (if possible) with your surge indicator. I'm just starting a new layout so I think I will test as I go and see what happens. It will be my first real layout (non temporary) and there are plans to expand as budget permits, so it's all still subject experimentation and changes as I go.

Just so I understand, the runaway train syndrome can definitely be helped by having the sidings individually controlled with a toggle switch.  I guess my question is when I remove the conventional or legacy feature on my DCS remote for any individual MTH diesel will that help?  So far so good.  I haven't had any issues.  I actually was able to run both engines on my layout and run them and park and shut down the locomotives down.  If I was to have the toggles does the DCS have to relearn the layout?  Is there plans to address the runaway train syndrome with a new firmware update?  I am sorry to be redundant and or ask something that has been probably asked before.  I have a feeling this is what happened to my one of my  locomotives which ran off?

Just so I'm also clear, I can't find a soft key command to make the loco wake up in conventional mode neutral.  All I find is FCM, which toggles between Conventional and Command Control, and FLM, which toggles between Conventional and Legacy.  Neither of these offer Conventional On/off.  Direction lock is OFF.

What am I doing wrong?  When I toggle FCM from Command to Conventional, the engine takes off forward.

Tom

You're using the wrong key.  Just do a startup or shutdown from the main keyboard, keys 3 or 6, and it'll hop back into command mode.

I felt the explanation didn't explain how to avoid runaways (3 locos at once taking off evidently in conventional mode).

That';s because your runaway engines have nothing at all to do with DCS or the watchdog signal.

how do I tell my PS3 locos that, if they start in conventional, to start in neutral?  Is that in your book somewhere Barry?

You don't. They come up in conventional in neutral unless they've been locked in a direction conventionally.

The 1N5257B is a 33V Zener diode.  That's the key ingredient if you will of the surge/transient detector.  The Zener voltage determines the size of the surge that will flash the red LED(s).  You'll pay more for shipping at DigiKey than for all the parts needed to make a basic detector or even the more sophisticated hirailer suppressor/detector.  Yes, the hirailer circuit indeed indicates as well as suppresses.

The 1N914 is a so called signal-diode that would be OK to use in place of the 1N4xxx in this application but is not a substitute for a 1N5257B.

Again, what I find most interesting is this runaway syndrome seems to have a location dependency based on some reports.  That's why I think a traveling surge detector might have value.  Each TIU channel has an internal suppressor but a suppressor can only suppress what's presented to it - a transient surge at one point of a power district can present differing size/shape from one point to another point 10 feet (or whatever) away.

Keyboard?  I have DCS.  Am I making the mistake of comparing DCS to Command Control?

Barry,

I was trying to address speed issues as related in your book on pg 171.  You indicate that you should use FCM soft key and set to Conventional mode OFF, and FLM Legacy mode to OFF. 

When I look at my soft keys for my PS3 locos, FCM just toggles back and forth from Conventional to Command, and when conventional is selected, the loco takes off at a speed dictated by the xfmr voltage.  There is no Conventional OFF selection - I assumed that setting it to Command was Conventional OFF.

FLM just toggles between Conventional and Legacy - no Legacy OFF.  Should I assume that this should be set to Conventional to be Legacy OFF?

Since the loco takes off forward when I set FCM to Conventional, does that mean it's locked into Forward conventionally?  If so, how do you unlock conventionally, or lock to neutral using the DCS control?

Sorry, but it's not clear to me.

Tom

Tom, the only time, after over 10 years running DCS I had a loco start off at high speed in conventional immediately on applying power to the track, was a new PS3 within the last month.  It would always start in reverse.  I called MTH and was advised to do a "conventional reset" on the theory that somehow the loco had gotten locked into reverse.  Using my Z4000, and with TIU power off, press the whistle once and, with 1/2 second waits, press bell 5 times.  You should hear two blasts on whistle, to signify a reset.  If you don't get 2 blasts, try again.

I suggest you try this; it worked for me.  "Factory reset" and "feature reset" don't do the job.

Robert, so you connect the Z4000 directly to the track, bypassing the TIU, or can you run passively through the TIU, say on fixed 2, without the TIU being powered?  What voltage do you set on the Z4000 to do this?  I've heard keep it below 8V?

Tom

Ok, I got it on the 914's I have a bunch of the 4xxx's in different xxx numbers also. I usually start a list at Digi-Key and don't order it until I have a few items built up. If I go start looking around there I always find more stuff to add. Their USPS first class shipping is really cheap when they do ship though. Very reasonable these days.

I see your point about the hi-railers design, it doesn't travel. I saved their schematic also, that might add a thing or two to my parts order with the 5157's. When I come across something new to me like this I usually order extra (depending on pricing), just in case. If they are only 25-50 cents each, will probably get 6 to 12 or so.

I enjoy fiddling with these things, I'm just not smart enough to come up with my own designs. Started out to learn electronics many years ago, got a decent job doing something else while taking classes and stayed with it for almost 40 years, never got back to the electronics learning. I do really enjoy reading posts here from you and GRJ and several of the others here that are always coming up with these designs for these things. And I also appreciate your help and all the help from the others here as well.  

Either connect Z4000 directly to track, or go thru FIXED 2 as you state.  But be sure the TIUs are off (red lights out).

Now, let me refine the procedure slightly.  As soon as track is powered, loco may want to move, so up the voltage slowly until you hear the board click & maybe a volt or so more.  Have a hand on the loco to keep it from moving.

I have never run a DCS loco conventionally, but I know there is a direction lock softkey button on the remote.  Never having used it, I don't know what it does, but you want to make sure that it isn't set for some unwanted setting.  See paqe 37 of Barry's book.

What if you don't have a z4000? Any way to do this through your DCS system? I thought the factory reset did it all?  Just curious. 

The keypad on the remote.

rtr12:  Since I don't run DCS locos conventionally, I don't know how to do it with another transformer.  Someone else please chime in.  My guess is to try pressing the whistle button once, fairly quickly, then the bell button after 1/2 second pauses. 

Mr. Magoo: No, if toggles are installed, DCS doesn't have to relearn layout.  But, before using the READ button, be sure all toggle switches are on or locos will wind up in the black hole called "inactive engines."

Thanks, I don't run anything conventionally either, nor do I own a transformer with a whistle and bell button, only PH-180's. Guess if I have this problem I can take it to my LHS, they have a z4000 set up there for their test track. That's where I get all my engines anyway, and 90% of the rest of my train items.

I've reviewed the settings in Barry's book, but some of them don't match up to what is shown in the PS3 menu.

I assume you have to do the conventional reset on a test track, once for each loco?  I'm guessing that trying that on all locos at the same time might yield odd results.

Tom

I think wisdom dictates use of the test track.

tk62,  Since you only have this problem with one engine on one spur.  Make sure track is clean, and make sure pickups and both outer wheels with out traction tires are clean.  Gunk on wheels and center pickup rollers (Internal pin) can cause issues.  G

G, sorry, the problems have manifested themselves on multiple engines at different times, on different spurs.  A TIU reset seems to have fixed most of them - for now, I say with caution, since I don't know what caused them to start with.  I have one engine left that has a problem on multiple spurs - it stops responding to DCS commands after backing into the spur.  I'll try resetting it and cleaning the wheels and pickups and see if it improves.  Funny, but that engine does fine on the main track, and all other locos do fine on the whisker spurs in question.  Must be a marginal problem.

The other issue I was discussing with Robert was how to test and fix any locos being stuck in a forward or reverse speed in conventional mode, since that is how they would wake up on a spur that had been shut off via toggle when the TIU first sent its WD signal.  I know they should revert to neutral, but I've heard some stories about engines being shipped stuck in conventional forward.

Just trying to be careful and thorough - when the 3 took off towards the TT at the same time, it was an experience I don't want to repeat.

Tom

Depends what you mean by "odd".  As RJR says, you should get a double horn-blast (if diesel) or whistle-toot (if steam) acknowledgement if an engine successfully interpreted your conventional button pattern.  If you have multiple engines on the track, you would hear a chorus of sounds which might be odd since you might not distinguish if one of the engines didn't acknowledge.

Note that a conventional reset (W-B-B-B-B-B) sets the engine to start in neutral when powering up in conventional.  The engine will still take off at full speed forward if there is a subsequent momentary dropout in power (from a flakey toggle switch, loose wiring, whatever).  So what was suggested elsewhere was to lock the engine in Neutral (W-B-B-B while engine is in Neutral) for conventional operation.  So in additional to powering up in Neutral, subsequent power dropouts will not cause the engine to take off.

As suggested earlier, consider using the volume trimpot on the engine to set the conventional sound level to some known level (loud or soft) different than how you normally set volume for command.  This can be a useful indicator that an engine has powered up in conventional when you wanted it - or thought it - powered up in command.

Stan, I wasn't aware of the W-B-B-B locking into neutral.  MTH had only suggested the w5B to reset it.  So if one does that, the loco can't be run in conventional, but will start up with conventional sounds?  Correct?

Correct.  You can lock an engine in Neutral, Forward, or Reverse depending on what the engine is doing when you activate the feature using W-B-B-B.  Then, when the engine initially powers up in conventional, the sounds/lights come on at the volume level set by the trimpot and be locked in N F or R as set.  Subsequent presses of the DIRECTION button (or intermittent track voltage dropouts if you have them) will not affect N F or R.

Note that this is "normal" operation; what was discussed earlier in the thread was the possibility of a power surge/transient (the most likely culprit) bypassing this lock and causing the engine to take-off.  I'm not sure the final story has been written on that, nor if there's a bullet-proof solution at this point.