Runaway MTH engines

Stan,

Must this be done from the transformer with the TIU off, as Robert said, or can I do this from the DCS remote while in Command mode?  Is there a way to read out or know what the loco is locked into in Conventional mode without having it take off?

I guess you're also saying is that the best "bullet proof" solution is to connect all spurs/whiskers with toggles and turn on only the spur you want the loco to start from, to prevent any abnormal "accidents"?

Tom

Tom, what I said is what MTH's VP Jeff Strank told me.

Stan, I'm not certain from the problem description whether locos start moving immediately upon or within 2-3 seconds of power up or some time thereafter.  If thereafter, the probability is 2 sparks somewhere on the layout.  I do note that on my layout, tracks get power a few seconds after I throw the single 120-volt switch that turns on transformers and TIUs.

AFAIK you can only lock the engine's conventional motion (into N F or R) using a conventional transformer - in other words you can't effect it by pressing the Whistle or Bell keys on a DCS remote.  Likewise, the DCS remote cannot indicate or read out what kind of conventional direction locking, if any, is in effect.  I'm sure one of the gurus will correct me if I am mistaken.

Practically speaking, since you'll need a conventional transformer to do this, as pointed out earlier you can keep the track voltage to a relatively low voltage when messing with this - say, 10V or so.  In other words, you can effect the conventional locking feature with conventional voltage levels on the track (as one would expect).  So to confirm the engine is locked in neutral, you would press the DIRECTION button a few times noting that it never moves.  And if for whatever reason, the Neutral locking did not "take", at least the engine will not rocket off at 18V.

That seems to be the consensus opinion.  I don't know if it's bullet-proof other thought I've never seen and engine move (intended or un-intended) without track power!  I say this in all seriousness since I'm imagining a battery-powered runaway engine - how do you stop it?!

So then you just deal with the minor inconvenience of sending a DCS command after toggling on the spur.  Or, as discussed in the other thread a DCSRC attached to a spur can "automatically" generate a watchdog signal so any engines on the spur power up dark/silent and in command-mode.

I have a couple of the DCSRC's from the first 2 RTR sets I got from MTH - I could try them.  I'm assuming you need one per spur, since wiring one across multiple spurs will power up all spurs at once?  Also, I thought I remember you should wire them passively, that is, only the DCSRC's output terminals are connected to the spur tracks, and no input voltage?

Thanks

Tom

Right...one per spur.  And right again...wired passively to the red/black jacks with nothing connected to the input barrel/coax jack.

If you try it I'd be curious to hear whether it turns out to be a ho-hum take-it-or-leave-it...or if you find yourself lurking eBay or train meets for bargain-priced DCSRCs from starters sets!

I think lurking might be in order if it works.  I only have 2 of them, and 8 spurs.

Yes, this thread has presented many scenarios and it's still not clear to me that all are explicable.  What I find interesting is now that MTH ships starter sets with the DCSRC, new O-gauge users might never have seen/used a conventional transformer.  I can imagine someone fiddling with the wiring, having the engine come up in conventional and taking off at 18V.  That could be a rather startling introduction to conventional .

There are reports that for PS-3 a DCS factory reset will not effect the Conventional direction lock.

The easy test is to put the engine on a conventional test section and apply power.  If it moves it is locked in a direction.  If it doesn't and a cycle of power doesn't get it moving, it may be locked in neutral.

To unlock engine when moving keep voltage low, less than 10V and do the unlock.  The conventional reset only works in neutral.  Do both a conventional reset and DCS factory reset and you should be back to a factory baseline.  G

GGG, I don’t understand your statement that conventional reset works only in neutral.  My PS3 somehow got locked into reverse, but a conventional reset worked to unlock it. 1W5B.

I was thinking this might work - using one of these 12V SPDT relay modules (SainSmart?) to switch power to my 8 whisker spurs, but using a 16 channel version to also simultaneously switch an MTH DCSRC to the spur being accessed to send a watchdog signal only to that spur.  I think that would allow me to only have one DCSRC to use with the 8 spurs, without shorting spurs together unless I intended it.

Question:  Althought it seems like many are using an AIU or something called Arduino to switch the relays, since they appear to be gnd actuated, can I just use a low power toggle switch at a control panel to switch the ground to actuate the relay?  I assume this ground contact is continuous rather than momentary?

I suppose the alternative would be to use DPDT high current switches on a control panel to accomplish the same thing. 

In either case, can you leave the gnd of the DCSRC permanently connected to all spurs, and just switch the red terminal from spur to spur to generate the WD signal?

Tom

Do you happen to know if the conventional reset can be done with a DCS system? Or does it have to be done with a transformer only?

Do you happen to know if the conventional reset can be done with a DCS system? Or does it have to be done with a transformer only?

It can only be accomplished using a transformer.

Tom, this is overkill.  I have simple toggle switches on each whisker and the turntable and have no problems.  Don't forget the csrdinal rule: KISS.  You have some other problem which has to be diagnosed.

Thanks Barry, was afraid of that. I don't have a transformer, but I don't have the problem either, at least not yet.

I have had issues doing a conventional reset with engine moving.  I will need to look into that more, but I thought the documentation required it to be in neutral.  G

Not true....MTH is very easy.

1) Place engine on track

2) Power up track

3) Press "read" on DCS controller and/or "Menu/Add Engine/MTH.

DONE!

I use no light bulbs to increase signal, have original Revision TIUs from the first release over 10 years ago.

Just don't ask me about certain PS3 locos!

(cough)

GGG, if it's locked in one direction, you have to apply voltage slowly and catch the loco by hand.